Guide updated 07/17/2012 : some mistakes corrected!
Netinstall and a lightweight desktop
I recently got an old iMac G3 and felt the need to replace the crappy existing MacOS 9 system with my favorite system : Linux of course!
After a mandatory RAM upgrade (from stock 64M to 512M), I found that the CD drive is extremely picky/worn-out and wouldn’t boot any burned install CDs…
But that’s not enough to stop me, since those iMac models support booting from the network.
I first tried to netboot Debian Squeeze on it, but there were some issues (yaboot started but couldn’t load the kernel).
After some research, it appears that Ubuntu has an updated netinstall iso which just works!
Agent OSS 