The Miami-based company claims to be "reinventing the wheel" with its Open Computer, formerly called OpenMac -- for $399.99. Psystar tapped into efforts known as the OSx86 Project, and its goal of running OS X on a PC have been realized. Even the latest releases of OS X can run on PC hardware, Psystar said, but compatibility can be an issue.

"Why spend $1999 to get the least expensive Apple computer with a decent video card when you can pay less than a fourth of that for an equivalent sleek and small form-factor desktop with the same hardware," the company's Web site says.

Challenging Apple

Apple has made it clear that Open Computer violates the Leopard end-user license agreement (EULA). The agreement forbids installation of the operating system on third-party hardware. Apple CEO Steve Jobs may have taken the violation personally, suggested Ilan Barzilay, a member of the litigation practice group at Wolf, Greenfield & Sacks, P.C.

"When Jobs left the company in the 80s, there were internal struggles about how to keep the company profitable and how to increase market share. Apple decided to take the Windows route and license the operating system, and we saw Apple clones," Barzilay recounted. "When Steve Jobs took control of Apple again, he cut that off."

Now, news reports indicate that Psystar is challenging Apple's EULA. The company is using the "unfair monopoly" card, claiming Apple overcharges for its hardware and its EULA might not hold up in court. Legal analysts said the dispute could ultimately wind up in a federal court.

Is Apple Running a Monopoly?

Making the case for an Apple monopoly will be tough, Barzilay said. Antitrust issues are typically decided by defining the relevant market. If Psystar manages to convince the court that the relevant legal market is people running OS X, then that could fly.

If you define the market as personal computers, on the other hand, Apple's market share compared to Windows machines is still small. Apple's U.S. PC share is up 32.5 percent in the first quarter, but that still only gives Apple 6.6 of the total market, according to Gartner.

"Now that Apple has created the version of the operating system that is licensed to run on Windows software, there are a number of users who are choosing that option," Barzilay said. "If the relevant market is personal computers, there's no way you can say Apple has a monopoly. It's a question as to what the specific legal arguments are going to be."

What's in the Open Computer

The Open Computer offers a 2.2-GHz Intel Core 2 Duo processor with 2GB of DDR2 667 memory and integrated Intel GMA 950 graphics. It also boasts a 20x DVD+/-R drive, four USB ports and a 250GB, 7200-RPM drive.

The closest machine Apple offers is the Mac mini, but the specs are not the same. The mini sports a 1.83-GHz or 2.0-GHz Intel Core 2 Duo processor with an integrated Intel GMA 950 graphics processor. It offers 1GB of DDR2 667 memory, though it can support 2GB.

The mini sells for $599. Apple's machine comes with iLife, Microsoft Office 2004 for Mac Test Drive, a 30-day trial of iWork and Front Row, as well as other standard applications. The clone doesn't offer those extras.