Jamendo is a source of free and legal music downloads. The music on Jamendo comes from the artists who upload it themselves. While not all of the music is licensed for re-use, there is a substantial collection of music labeled with a Creative Commons license. As always, before re-using any of the music you download make sure it is labeled for re-use.
Applications for Education
Jamendo could be a good source of music downloads for students to use in video and podcast projects. Some of the music does come with an "explicit" label so you probably don't want to send young students searching on Jamendo on their own. In that case it would be better for you to build a collection from which students choose.
Here are some related items that may be of interest to you:
Sound Bible - Free Sound Clips
PodSafe Audio - Sounds for Podcasts
Free Music Archive