You could use a standard flash-based MP3 player, or use HTML5 audio to play it.
Not all browsers support MP3 with the audio element out of copyright concerns, though, so you'd have to convert it to OGG.
One way you could do this is with a BB Code Media Site.
Media Site ID: html5audio (or just "audio")
Embed HTML:
Code:
<audio src="{$id}" controls>HTML5 Audio not supported</audio>