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And given that Mac OS X has many of the features of Linux without the pains of installing or managing unix software, you may really want to consider getting a Mac OS X compatible machine and selling your emachine. Linux can be harder to find software for than even Mac OS X, and harder to install software on than Mac OS X. Basically any Mac with built-in Firewire can have Mac OS X 10.4 installed, assuming it has 256 MB of RAM, and 5 GB of free disk space, though I would double those requirements to work comfortably with bigger hard drives and more widgets. As others have said, these hacks which let you run Mac OS X on a non-Apple machines, are just that, illegal hacks. The license agreement allows you to install Mac OS X only on Apple Macintosh computers. Any attempts to upgrade such software may fail as, they aren't really tested for the non-Apple machines. Intel Macs use a different firmware chip too than non-Apple machines which can't be duplicated on non-Apple machines. You can however, install XP on an Intel Mac very easily as my FAQ here shows there are several solutions:
http://www.macmaps.com/macosxnative.html#WINTEL