http://homepage.mac.com/bner/iblog/B...3/E1995539341/

Check out the above link. I had a 14" ibook but was never able to get linux working on it. In fact I sold the ibook because I was fed up with trying and failing. I have run debian on a old world mac.

In my opinion linux ppc support is about 4-5 years behind x86.

I'm not sure what you want knoppix for on your powerbook but if you are looking for open source software for the mac you might look at setting up fink (do a google on it).