SoundCloud – a free file sharing service for musicians – has added a Creative Commons option, so you can share music in ways that let others freely copy it:

The CC license support on SoundCloud is pretty straight-forward. You can pick a license when you upload a track, and you can set a default license in your settings.

There are three main modes; All Rights Reserved, Some Rights Reserved, and No Rights Reserved. The default is All Rights Reserved, which means you own all rights to the works you upload.