This post is part of our feature on Money Winners of 2008. See all 20.

Think you could live comfortably on $23 billion? That's what each of the four Walton heirs live on today thanks to the company built by their father or father-in-law Sam Walton -- Wal-Mart (NYSE: WMT). Walton heirs were beat out by only three other billionaires for the top spot on the Forbes 400 Richest Americans list in 2008 -- William Gates, Warren Buffett, and Lawrence Ellison.

Only two of the Walton heirs have anything to do with the company from which they get their riches. S. Robson Walton is chairman of the board and he has served on the Wal-Mart board since 1978. Jim Walton is a member of the board, which he joined in 2005. Alice and Christy Walton, who are not involved in the running of Wal-Mart, do get the richest women in America title thanks to their Wal-Mart holdings. The Walton heirs recovered from a rough spot in 2006 when their stock holdings dropped to $18 billion and they fell to 17 to 20 on the Forbes list.

So who are are Walton heirs?

Jim Walton ($23.4 billion and #4 on the Forbes list), son of Sam Walton, is 60 years old and married with four children (future Walton heirs). He lives in Bentonville, Ark., and chairs the Arvest Bank Group. He got his BA at the University of Arkansas. He joined the Wal-Mart board in 2005.

One of Sam Walton's relatives is joining the Wal-Mart (NYSE: WMT) board, so there is, of course, speculation that he may one day get the top job. Of course, he probably does not have one iota of qualification to do anything at the world's largest retailer.

According to The Wall Street Journal, "Gregory B. Penner, who was nominated to the board in April, is the 38-year-old son-in-law of Wal-Mart Chairman S. Robson Walton, himself a son of company founder Sam Walton." That is not entirely true. He was the CFO of the company's Japan operation which has lost hundreds of millions of dollars.

Penner's parents are sex therapists. An excellent background for running a massive chain of big stores.

Douglas A. McIntyre is an editor at 247wallst.com.