For many years Apple has fought tooth-and-nail to prevent people from making "Mac clones", to the point of lawsuits and other intimidation. They weren't able to do this forever, though, and most recently a company called Psystar has been somewhat successful at making a pseudo-Mac. Now, Psystar has set their sights beyond the desktop and are ready to take on Mac servers.
Their latest endeavor, dubbed the OpenServ series, launched this week with the ability to run OS X Leopard Server at cost significantly below Apple's own servers - upwards of $1200 in savings the company claims. They are offering two models to start with, and also pitch them as being Windows compatible, though clearly that isn't their aim.
The hardware inside their servers on its surface looks decent, coming with Quad-core Xeons if needed, large amounts of RAM and plenty of storage. Whether or not Apple pursues them for more toe-stepping remains to be seen.