Almost a year for an answer, but an
answer be better than none ...
You've got two chances of WfMS appearing on your PowerPC beauty: sweet F.A. and bugger-all. Sorry chum. As much as I love the efficient and elegant PowerPC architecture, we're talking seven year old technology here, and Greg & Mak & the team would all be on relatively new Apples, and as such they would be taking advantage of the newer frameworks that 10.6 and higher provide.
Your best music-player is still Audion, now a freebie from Panic Software. Download your installer here
then collect your free serial number here
(In the FWIW Dept: Did you know, that when Steve Jobs went hunting for software to become the front end for the original iPod, he went to Panic first? Cabel said "No", as did the creator of 'AMP Radio', leaving him with the third choice, SoundJam.)