Actually they raped BSD and develop the propretary GUI on it ... But still ......

Like Gorn said, you can run Linux on it and I think it's called PPC (I'm not sure) and the other one is "yellow dog" ... Apple has good hardware but price is too high for me ......
www.linuxppc.com www.yellowdoglinux.com www.debian.org www.mandrake.com www.linuxfromscratch.org