Here is an MP3 Player AS2.0 class I made. The idea was to make it very easy to implement in flash, and then to allow the skin and playlists to be editable via XML. Compatible with Flash Player 7 and up.
Critique it, use it, add to it. If you make improvements, please post them here for everyone to use! Feel free to post links to your implementations of the player as well (assuming anyone decides to use it!).
Demo and MX2004 Source - version 1.2
(By the way - the demo skins could be a lot better. Just putting something up there to show.)
Version 1.2 - Fixed bug introduced in 1.1: Playhead was not being triggered by play/pause button.
Version 1.1 - Fixes small bug: Player would not automatically go to next track if playOnLaunch was set to "true".