The Wall Street Journal (subscription required) reports that the FBI is looking into a potential computer-security breach that resulted in the theft of tens of millions of dollars from Citibank by computer hackers.

These hackers appear to be linked to a Russian cyber gang who targeted Citigroup's (C) Citibank subsidiary, including its North American retail bank and other businesses. This attack was detected over the summer, but there is a chance that it could have happened as much as a year earlier.

With President Obama highlighting the national importance of cyber security, we turn to technology specialist Gregg Early to find the best investment ideas in the sector.

Noting that "cyber security is one of the biggest new sectors in the information technology industry," the editor of Personal Finance offers a trio of buys in the field -- McAfee (NYSE: MFE), Versar (AMEX: VSR), and Unisys (NYSE: UIS).

The advisor explains, "In exchange for an annual fee, McAfee allows users to download the basic security software and regular updates. These frequent updates are essential because virus and malware threats are constantly evolving.

Faced with a legal and public relations fight it probably couldn't win, News Corp's (NYSE: NWS) MySpace caved into pressure from states attorneys general and agreed to hand over names and addresses of sex offenders who have opened profiles on the popular social networking site. This is a long overdue move, but it's only a start.

Not all sex offenders are stupid enough to register on MySpace under their real names. There also are plenty of creepy people seeking to hurt children who aren't sex offenders. It's a scary world.

Plus, there are other MySpace dangers for young people which the site needs to address in order to allay the concerns of parents. Shareholders also want MySpace to avoid legal battles with law enforcement so that News Corp can make the site a focal point of its Internet strategy.

Many of my perspective friends on MySpace want me to pay them to perform a private X-rated show over their Web cam. Celebrities ranging from porn stars to comedians use MySpace to market themselves to wannabe hipsters. The commercials aren't always easy to spot either.

But even the best cybersecurity is no substitute for common sense and good parenting. Many young people share too much of their personal information with strangers on MySpace and other sites.

MySpace has already received subpoenas from a dozen states for names, registration data and profile information, according to the New York Times. States will need search warrants if they want more specific information like email messages.

Let's hope that MySpace's actions back up its rhetoric.