It's got a hell of a purdy startup screen. Doesn't seem to like my athlon
though. I'll have to try it on my p4 or p3 later:
http://www.gnu-darwin.org/index.php?page=install-x86
They seem to have most linux apps in their distribution.
Just in case you were wondering:
http://developer.apple.com/darwin/projects/darwin/faq.html