Not sure what you ended up doing for this buuttt:
There are a few web interface plugins for winamp that control Winamp...
WAWI is the most basic one that works well but I haven't tried it too much on PPC Browser... can't seem to get it to come up right but it's open source I believe so can be tweaked...
http://www.flippet.org/wawi/
Another web interface I just ran into is ajax which appears to work well with Opera but I haven't seen the functionality that WAWI has as far as browsing the file system and queueing songs up...
http://www.ajaxamp.com/
What would be really cool is if someone were able to develop an app that integrated with WAWI for the PPC... something that would communicate with the web interface through a tidey application instead of having to go through the web browser. That's ideally what I'm looking for.. an app that will allow me to control winamp.