Gratisvibes is a newish blog reviewing and recommending CC licensed electronic music:
Gratisvibes aims to lead readers to the best of Creative Commons-licensed Electronic Music on the web, spreading the word for greater musical freedom for both artists and listeners alike.
The following mixes were made to be used in a classroom setting as background and/or intermission music. In the class I am attending at the moment we frequently work on our own and then meet back up after a pre-determined time. For example we would go work at computer terminals for thirty minutes or take a break for fifteen. The mixes can be used as a musical stopwatch playing 5, 10, 15, or 30 minutes of work/study friendly music.
The samples are of course from ccMixter and fully attributed.
You can be a CC tastemaker too.