I know a lot of people have asked this question, but I still will take my chance because I haven't received a substantial answer yet. I need an easy and reliable player. I need the MP3 to be useable from the code behind. Most of the players I found ether have it embedding on the page or as a fixed file of some other sort.
I do not think that you are going to find it.
The problem is that the code behind executes on the server, but for the user to hear the music the mp3 player must be on the client.
You could try a streaming solution using a silverlight player.