Yellow Dog Linux
My advice is to scroll to the bottom and find the newest version that has "PS3" in the link.
Currently the latest version is yellowdog-5.0.1-phoenix-20070511-PS3.iso
YDL Download Mirror
Edit 11/27:
Well I installed YDL on the PS3...I have to say it wasn't that hard but did take a little while. I haven't had a chance to play with it to much yet but so far I like it. It even comes with GIMP as one of the pre-installed packages...for all you graphics guys. I did notice one thing that was kind of funny...It didn't support my Microsoft mouse, I had to use my Logitech one. Again I will report back with new details on this as I find more.
Edit 11/28:
Ok I played with Linux all day and really don't understand how to a thing with it. I couldn't even get Java installed. Anyways I will leave this thread open if anybody else, maybe who is more familiar with Linux, wants to tackle it. I have all the files you need so just let me know.