I am trying to write a little application that will play back wavs / mp3s. I'd like to have independent control over both the pitch and the speed which they are played back at. For example, I'd like to be able to play something say 75% speed without altering the pitch, or play something a half-step higher without changing the speed. Nearly any combination of pitch/speed changes. I have been searching around for something that will do it, but I haven't found anything definitive yet. Will FMod do what I want? TIA

Yup. The FMod Documentation is the best you'll find. I haven't played around with the speed/pitch at all, but it's in there somewhere.

If it's anything like Open AL, you've gotta modify the frequency to change the speed of it, and that's done before you stick it in the buffers. As for the pitch, you can control that as it's playing back. I found FMod harder to understand Open AL, but since I've already been using Open GL, and the context is similar, it was easy to learn. If you find you're still struggling with FMod after going through the tutorials and such, maybe you should have a look at Open AL.