Okay, WinUAE is working great except:
1. I only have sound in games, not workbench
2. For some reason, I can't setup the keyboard for game usage....not sure why
I would like to play mp3's from Amplifier in Workbench 3.9 etc.
As Bbond007 suggested it's most likey that ahi isnt set up and paula is being used exclusively (its a bit inaccurate, but for conversations sake, ahi parallels p96, but for sound). If youre using OS3.9 it should be there already (if I recall correctly), and you just need to set it up (in prefs). Paula (amigas custom sound hardware) can be used with ahi, but youd have to be madman to use it if you have other options, especially with Winuae, whose performance will suffer for it (the less emulated the better, and paula, for a few reasons that dont need to be explained right now, really puts the screws to UAE)).
Ontop of that make sure you have mpega.library installed for mp3 playback.