I was going to ask that question myself as I'm a newbie to the PPC's 233Mhz chip myself :-D
So far I have only used FroggerNG.WOS to play AVI, MPEG and Quicktime videos with fantastic results. The PPC version of AmigaAmp for MP3 playback and ShowPPC for displaying photos at lightning speed :-)
I think you will be advised to use WarpOS instead of PowerUP.
A4000 Mad