Since it appears you have a dvd drive here is a link to Suse for the last supported build.. I've not installed this particular build, but looks like I need to try it out since it's the last on this platform..

http://download.opensuse.org/distribution/11.1/iso/openSUSE-11.1-DVD-ppc.iso

Note if you browse up from there on the site you can get to the older versions as well. Just look for the ppc variants and you will be fine.

Good luck