"We're adding Brazil's Vale S.A. (NYSE: VALE), the world's leading iron ore producer, to our model growth portfolio," says growth stock expert Stephen Leeb.

In his The Complete Investor, he explains, "This outstanding company offers investors simultaneous stakes in two key areas: iron ore-a commodity essential to any and all infrastructure projects-and Brazil's appreciating currency, the real.

"When it comes to understanding the importance of a commodity such as iron ore, the tale starts with China. Even with China's GDP growth again approaching double digits, the Chinese government continues to aggressively promote growth, offering consumers incentives to buy cars and investing in infrastructure, from roads to bridges to sewers to energy plants.

"BHP Billiton Ltd. ADR (NYSE: BHP) is well placed in coal, oil, gas, and uranium markets, making it a solid play in any investment environment," says global specialist Yiannis Mostrous.

In The New World 3.0, the advisor explains, "BHP Billiton is the only major listed company to that boasts such a diversified energy portfolio.

"Recently, analysts have unleashed an avalanche of upgrades for companies in the mining sector, coinciding with higher price forecasts for a wide range of metals.

"The main reasons for the recent upsurge in optimism regarding miners are strong economic growth in China and an anticipated restocking of materials in developed nations.

"I'm adding Bucyrus International (NSDQ: BUCY) -- a maker of mining equipment -- to our 'Wildcatters Portfolio' as a play on coal," says Elliott Gue.

In his The Energy Strategist, the advisor explains, "With commodity prices recovering and Chinese demand for coal picking up once again, Bucyrus has likely seen the trough in its new equipment business."

"Bucyrus' top end-market is coal, which accounts for more than three-quarters of the firm's business. Coal mining equipment includes draglines, a sort of giant scoop used to scrape away the overburden (rocks and dirt) that covers coal.

"Getting invested in precious metal for the long term is our end game," says Daniel Frishberg, host of BizRadio and editor of The MoneyMan.com Gold & Oil. Here's a look at two ETFs.

"It looks as if prices could go higher short term, especially if US dollar weakness continues. The risk of owning gold at today's price level is that net commercial short positions continue to increase.

"Attempts by producers and speculators to bid up prices are matched by increases in commercial short positions. Gold prices are being controlled not by physical buyers and sellers, but by futures traders.

"When most people think of Africa, images of business and commerce don't usually spring to mind -- more like wildlife, safaris and famine," suggests Nathan Slaughter.

In The ETF Authority, he explains, "But those perceptions are beginning to change as these countries continue to industrialize. And at the vanguard of this transformation is South Africa." Here, he looks at the iShares MSCI South Africa ETF (NYSE: EZA).

Slaughter explains, "Once a backwater country shunned by most of the international community, South Africa has made great strides over the past decade and continues to evolve. Fifteen years ago the government began an aggressive overhaul of South Africa's economy.

"Gold has yet to take off in true bull market fashion, but its chart suggests that it's coming," says Mary Anne and Pamela Aden.

In their top-notch The Aden Forecast, the resource experts discuss the outlook for gold as well as some of their favorite mining stocks for investors to consider.

"Considering that the Summer months tend to be slow months, we could still see some short-term weakness.

"More important, however, is the bigger picture as gold is poised to rise during the second half of the year." Here, they discuss their outlook and some favorite ming stocks.

"In the 2000s, as we've alternated between deflationary and inflationary worries, gold has been the only major investment to rise every year," says Stephen Leeb.

In his The Complete Investor, he explains, "We think that many miners are exceptional bets today. And among our favorite gold investments is one that we hold in our small cap value model portfolio: NovaGold Resources (AMEX: NG)."

"The case for mining stocks is that the price of gold rises faster than miners' costs, allowing margins to increase.

"After enduring one of the worst slumps on record, we're beginning to see a rebound in all major commodities market," says Lee Lowell, adding "But one commodity stands out in particular -- natural gas."

In Xcelerated Profits Report, he explains, "This could represent the best buying opportunity in several years." Here's his review of the United States Natural Gas Fund (NYSE: UNG).

"As it so often does, it's no surprise to see the energy market leading commodities higher over the past few weeks -- specifically, crude oil and natural gas.

"With its strong balance Plum Creek Timber (NYSE: PCL) will be able to weather the real estate storm," says growth and income expert Stephen Leeb in The Complete Investor. Here is his look at the timber play.

"Plum Creek, which was added to our model portfolio in November, is the largest and most geographically diverse private landowner in the U.S. and owns more than 7.4 million acres of timberlands in the Pacific Northwest, the South, and the Northeast.

"It's hard to find any good news these days but I was pleasantly surprised with the third-quarter railway results, as almost all of the 'class 1 carriers' reported better than expected earnings," notes analyst Tom Slee.

The contributing editor to Gordon Pape's Internet Wealth Builder explains, "Several rail stocks are starting to look attractive at these depressed levels and Burlington Northern (NYSE: BNI) remains my preferred choice in the group." Here's his outlook.

"Even with the economic downturn starting to bite, reduced fuel costs and increased freight rates offset lower volumes. Equally important, the companies remain cautiously optimistic despite the miserable outlook.

"They are confident that further freight rate price increases in the 4% to 5% range are sustainable and will still allow them to undercut inefficient truckers.

"Unfortunately, none of this prevented the stocks from being battered during the market collapse. However, I think that fourth-quarter profits are likely to remain strong and the longer term outlook for railroads remains favorable.

"Burlington Northern continues to power ahead. A shrinking economy must eventually take its toll but there was no sign of any weakness in BNI's third-quarter results. Operating earnings came in at $1.91 a share, up 29% from $1.48 in 2007.

"Gold is now looking stronger; it is time that investors have gold in their portfolios," says Curtis Hesler. In the The Professional Timing Service, he looks at gold's seasonal patterns.

"I think they will rush to commodity-based assets because of the serious underinvestment phase the commodity sector is involved in now. This will lead to shortages and very high prices down the road in all commodities.

"Once the dollar begins to roll over, gold will be an instant benefactor. It is already looking stronger in my technical work, and it is time that investors should have gold in their portfolios. I still recommend that you put new money into the major gold miners only.

"We are approaching an interesting seasonal period for gold. Years ago, the Stock Trader's Almanac used to specify a seasonal trade in gold.

"Their study showed that if you bought ASA Ltd. (NYSE: ASA) at its low in November and sold it at its high in the first quarter of the next year, you would have averaged a gain of 87.8%.

"Crude oil remains deeply oversold on an intermediate-term basis, suggesting a rally sometime in the early fall," says Dennis Slothower.

The editor of Stealth Stocks looks to Petroleo Brasileiro SA (NYSE: PBR) as his latest "stock of the month." Here's his review of the Brazilian firm that is now the world's 8th-largest oil company.

"The founding of Petrobras was authorized in October 1953, with the objective of executing, on behalf of the federal government, the activities of the oil sector in Brazil.

"Over the past five decades or so, the company has become the country's leader in the distribution of oil products, an activity not covered by the government monopoly, and today it is internationally acknowledged as the eighth-largest oil company in the world.

"Leading the sector in the development of one of the most advanced deepwater and ultra-deepwater technologies for oil production, PBR was twice (in 1992 and 2001) awarded the Offshore Technology Company (OTC) prize, the most important award in the sector.

"Railroads are a play on three big secular themes: the drive for increased energy efficiency, growth in coal and the agriculture boom," says Elliott Gue, a energy sector expert who has just returned from Japan where he was covering the G8 Summit.

Meanwhile, in his The Energy Srategist, he states, "Railroads are now among the most fuel-efficient forms of freight transport available." Here, he offers a bullish review of Union Pacific (NYSE: UNP).

"My long-held thesis on the group has been that the railroads are no longer totally dependent on the US economy for their growth.

"It's no longer appropriate to look at this sector as viciously economy sensitive. The traditional relationship between the broader market and the rails has been breaking down for several years, but this trend appears to be accelerating.

"In 2007, according to the Association of American Railroads (AAR), the average railroad moved a ton of freight a distance of 436 miles on a single gallon of diesel fuel. That makes freight trains roughly three to four times more fuel efficient than trucks.

"Union Pacific is the largest railroad in the US and has long been one of my favorites. The company's network is nearly 33,000 miles long and is concentrated in the West and Midwest. It also offers a convenient example of the bullish forces at work for the rails, particularly in the coal and agriculture industries.

"As steel prices continue to climb, one company that is set to profit handsomely is Cleveland-Cliffs (NYSE: CLF)," says Bill Martin.

Adding to the stock's appeal, the editor of BullMarket.com explains, "Event-driven hedge fund Harbinger Capital has been an aggressive buyer of the stock." Here's his review of the situation.

"Shares of Cleveland-Cliffs have been on fire, up over 150% year over year and they have more than doubled year to date. The Cleveland, Ohio-based company is the largest producer of iron ore pellets in North America and a major supplier of metallurgical coal to the global steel-making industry.

"Cleveland-Cliffs benchmarks iron ore prices to the price of steel, so when steel prices rise, so do iron ore prices. The company said all of its North American iron ore mines are producing at or near capacity.

"Cleveland-Cliffs ended the first quarter of 2008 with $186.5 million of cash and cash equivalents and $600 million in borrowings outstanding under an $800 million credit facility. The company expects to generate approximately $700 million in cash from operations in FY08 as it sells through its inventory.

"Event-driven hedge fund Harbinger Capital was an aggressive buyer of the stock in May, paying between $76.96 to $104.75 a share to add to its position in the name. For the month, the firm spent approximately $338.5 million to acquire nearly 3.7 million shares.

"The number one reason I like gold is because of inflation -- now a big problem in the emerging markets and the major economies," says resource expert Eric Roseman.

In his industry-leading Commodity Trend Alert, he says, "One of my favorite companies in the world is Goldcorp (NYSE: GG)." Here, he looks at this gold mining firm.

"Inflation sits at a nine-and-a-half-year high in Asia at 7.5%, a 15-year high in the Euro-zone at 3.7% and in the United States it's at 4.2% -- if you believe government data in the first place. I don't. I say inflation is running closer to 10% in 2008, not 4.2%.

"The cost of living, mainly in food and energy, is now totally out of control and destroying business margins and eroding the purchasing power of consumers, especially in the emerging markets where food and energy consumption devours more than 65% of wages.

"It seems very obvious to me that Asian governments have now lost control of inflation. The same applies to the Gulf countries which peg their currencies to the dollar. And in Europe, the European Central Bank is freaking out because of high inflation.