Today, I rolled out the new Audio module (official site). This module allows you to post audio files as nodes in the Drupal system. You'll now find "Audio" as an option under the create content link. Audio allows you to upload your file (currently, we're supporting mp3, wav, and ogg formats). There's a generous 7MB limit per file. A form will prompt you for information about the track (artist, title, etc.).
I noticed one issue, which was my mp3 wasn't showing up with the nice embedded Flash player (the same one I use on jamesnotjim.com). I was getting a link to the mp3, which worked, but I wanted the embedded player. So here's a FAQ item: if the flash player doesn't show up, edit the node and make sure you have selected the file format (mp3, wav, ogg) from the drop down menu. If that doesn't fix it, set the sample rate as well (44K for most files).
The Audio module also add a link (titled Audio) in the left-hand navigation menu. And there's a submenu that allows you to browse by metadata (i.e. artist, album, genre, etc.). There's also a "Browse in progress" link, but I'll cover that in my post over another related module, Track 'n' Stack.
Please test this out by posting some of your own compositions. Just be sure they're your own--that you have a right to post them. I don't have time for legal troubles right now, mmkay?