Ok, so here is the answer. I'm not kidding it took a while and it was not pain free. But my basic steps were. Find an 10.4 Ubuntu ppc disk. I booted from that. What was not working was the wireless so I had to Ethernet from my computer. Right away Ubuntu wipes the disk and begins loading.
What is weird is I think I downloaded the server disk by mistake. It took forever to load, but I did have to use the live command to get it to boot. And the actual command was not Radeon 1024x 768@60 but instead change the refresh to @75.
Next I had to figure out how to change this from a server to a single computer reboot. I stuck in the 10.10 disk and looked up a command to install unity. It does this rather quickly, but it is live and the connection get stuck. Just unplug the ethernet connection if the disk is spinning and it will find libraries from the cd.
The next step is finding the 12.04 disk. That also provides the driver to get the internet working. Now if your like me you have an extra usb modem hanging around which works great but it take about 100 trials to get the hardware to recognize the airport card. Eventually it all works out.
Then there you are, wireless, desktop can find apps, and then maybe if your lucky your sound comes works right away. But aha. Flash is not working with Firefox and you can kiss watching pretty much any video goodbye.
Until you search and find flash.com which gives you linux drivers you install and voila, you finally have a working computer. It all works although you then wonder what the heck good is this? Simultaneously, you find web browsers that promise to work with tiger and leopard. So is Ubuntu a great install on PPC? IM not sure. It does seem to crash a bit, as the machine is ten years old. But then everything is up to date. And I do get to play Galaga on it, where I never could with the Mac OS (stupid emulators!)
Anyways. I am thinking Dual boot or just get rid of Ubuntu as maybe a web browser would give this old box more functionality and the drive would spin all the time. It is probably a little memory slow for even Ubuntu (as it screamed with Lubuntu on it), But it also shows that Ubuntu has a great place on a more modern mac, which I have triple booted and typing this for you. Gosh I'd rather use Ubuntu than the new stupid windows, which locks you into single screen applications at a time and then limits your functionality . But Ubuntu on this iMac is screaming fast and a pleasure to work with. Heck its even fast on my Intel 6 year old pc, which it also brought new life too.
So my next post will be suggestions how to add back tiger to be able to dual boot the powerpc, Otherwise, its just a novelty and I would get rid of it on that older machine.
Over all I am loving Ubuntu, thanks to all you developers!