do any projects support Linux on PPC? I've tried to attach to a number of projects but they all say the platform is not supported!

The platform name on BOINC doesn't even exist. For projects where the application has sourcecode available, you could compile your own, or search the web to see if somebody has an (unofficial) binary of it.

k, thanks. I was able to compile the software but couldnt attach to any projects. Well looks like my old clam ibook will have to goto waste unless i can get OS X on it.

I meant compile the specific software required for a project, not BOINC client itself. Usually BOINC would download the science application in binary form from the project servers, if there is a binary for your platform. If there is not, you can compile your own, say, SETI binary, and make BOINC run it using the anonymous platform mechanism.

SETI is the only one project, has binaries for Linux on PPC. Please look at the boinc third party site boinc.berkeley.edu/download_other.php for BOINC and SETI downloads.
SETI, SETI Beta and Leiden Classic are open source.

A list of the projects and there supported platforms is available at the BOINC WIKI : http://boinc-wiki.ath.cx/index.php?title=Choosing_a_BOINC_Powered_Project