Apple faces an unauthorised manufacturer offering a Mac clone based on an Intel Core 2 Duo processor.

Upstart company Psystar claims it will soon offer a $400 Mac clone running at 2.2GHz with integrated GMA 950 graphics. The manufacturer claims its machine will be compatible with Mac OS X 10.5 - even promising to ship the computer with the OS installed.

News of the computer broke yesterday, and initial reaction to the announcement was huge - the website experienced so much traffic that the servers failed to cope, confirming huge interest in an affordable Mac.

However, the company's attempt may well attract the wrath of Apple, which doesn't allow its OS to be installed on anything other than an Apple-branded computer.

"You agree not to install, use or run the Apple Software on any non-Apple-labeled computer, or to enable others to do so," explains Apple's license for Leopard.

Psystar is currently taking orders for its purported computer, but hasn't yet sold a unit. Apple's legal team seems likely to act once the first unauthorised Leopard-running clone ships.