Jamendo

(Sorry to sound like I'm spamming this, I really have no connection to the site! :) )

I've found Jamendo is a good source of CC material, especially if you browse it by tag:

http://www.jamendo.com/en/tags

It also lets you filter the results by licence type, popularity, downloads, plays etc so you can get to the better quality stuff that you also have permission to use.