Unfortunately, there doesn't seem to be a PPC version of Songbird. I have noticed that there are Fedora RPMs for both 32 and 64bit PPC, as well as source code at this url:
http://wiki.songbirdnest.com/Developer/Articles/Builds/Contributed_Builds
Which method would be the recommended way to get Songbird on my system - converting an RPM with Alien of building from source?
Cheers