I'm very tempted to try Squeeze on my StarMax now that I have it back in my possession. My iMac G5 is dead due to the caps being blown, but eventually that might see a repair if I'm feeling up to it (maybe I'll do that during the Spring Break I have next week).

Fedora dropped PPC but I hear it's coming back in 15. There's also CRUX. Arch, and I also heard about a Linux Mint port to PowerPC called MintPPC. That might be a better alternative to Ubuntu since they're going full-on with Unity as the DE.

http://mintppc.org/