It is currently Thursday, May 23, 2013 4:16pm
License music for commercial movies.
There are several more places to look (I did even more digging yesterday)
Music For Video
This list has music that's been cleared to use in video, but mostly non-commercial video.
Yes, I think Creative Commons (CC) Attributtion is the best one. Also, in the Search box, just hit enter. An advanced search form will appear. It'll have check boxes that allow you to filter music based on their licenses. When I did a search, there were around 600 tracks with CC. Could be more out there though. Good Luck!
I hope you'll post a link to your finished film so I can watch it :-)