Hi there.
I recently acquired a PowerMac G5 and wanted to try its processing power on some Boinc projects.
It came with Mac OS X 10.4 which meets the requirements for the latest OS X PPC client.
I tried to connect to BAM, but although the client tells me network access is fine, it won't talk properly to BAM.
I also tried the latest client for Mac OS 10.3.9 and upwards, but if failed accordingly.

Earlier this year I tried Boinc with an eMac running 10.4 as well which did just fine.
I can't access the eMac atm, so I can't doublecheck if it still is working fine, so for the moment I have to ask here if there are any known issues between the PPC client and BAM.