Here is my updated list of free music and sound effects for student (or other people) media productions. I encourage (read force) students in my video production classes to use audio from these sources for their projects. They also must provide attribution in the credits. I know that copyright law allows students to use copyrighted material for education purposes. But are we not encouraging students to share their work with the world? What happens when their excellent video project is uploaded to YouTube with copyrighted music? It is not longer a student project. I believe that it is important to show students how to use music that is legal and ethical to use, and will not cause their video to be taken down from YouTube.
I have also used some of these sites with English classes making book trailers or other video projects. After keeping track (no pun intended!) of this topic for several years, these are the best resources I have found and used regularly.