I agree with Matthew. It is far simpler to use royalty free music or Creative Commons Music.
For more see this post.
https://discussions.apple.com/docs/DOC-3921
Also, if you post on YouTube (which can then be shared with FaceBook), then you can try using copyrighted music. YouTube will flag it just like FaceBook, but sometimes YouTube will allow you to use it by agreement with the record labels. YouTube will put ads on your video and the revenue from the ads will go to the record label.
This is totally dependent on the owner of the music. They do not have to let you use it, and if you get flagged too many times, you can lose your ability to post on YouTube.
Also, YouTube has a library of tunes that you can license for a fee. In this case, you upload your movie to YouTube with no music, then add music on YouTube. You will have a lot less control of your editing this way, so it is for pretty simple needs.