not much up on the mac, will this work???
For Apple Macintosh G3, G4, and G5 computers, including iBooks and
PowerBooks as well as IBM OpenPower machines.
cdimage.ubuntu.com/.../ubuntu-7.04-desktop-powe\
rpc.iso

from here..
http://cdimage.ubuntu.com/ports/releases/feisty/release/

and there are others for you to play with :)
www.ppcnerds.org/index.php

and FAQ too..
https://wiki.ubuntu.com/PowerPCFAQ

The gereral answer is yes! Now you might have to play around with it, there
are PPC editions of the various Linuxs out there. Good Luck and if you use
Ubuntu let us know how it turns out.