Does anyone know of a good tutorial on the distinction between the MPMoviePlayer vs AVAudioPlayer vs MPMusicPlayer?

I want to play audio from an mp3 file available at an external URL.

Ideally it is played in an iPod-like audio view. I toyed with MPMoviePlayer but it appears to be more suitable for video, as when audio starts a "movie playing" message displays, the controls disappear and a white quicktime splash page displays.

I would like the standard ipod audio controls to display all the time, and to customize the image behind them.