During the development of my game I wanted to be able to playback MP3's using the PSP's media engine processor. Knowing that there existed a few libs already I decided to try and use one rather than reinventing the wheel.
The best and most powerful one that I saw seemed to be Sakya's example from LightMP3. So I download and tried to compile it but due to changes in the SDK it wouldn't compile.
After a little chat to IWN I had it fixed in a matter of minutes
So for anyone else that wants to be able to playback MP3, OGG or Atrac3 on the media engine on there game download this and your all set. It's really easy to integrate.
Note : I take no credit for this lib at all. It was made by sakya, all I have done is modify the source code so it compiles on the latest toolchain.