I had an opportunity to hear Barry Britt speak on copyright in the classroom yesterday. Barry is from Soundzabound, which in my opinion, is THE BEST subscription based site for royalty free music.
Barry made a great analogy for illegal downloading: just because you have a car that can go 160 mph does NOT mean you can drive 160 mph! There are speed limits that are enforced. Likewise for downloading: just because you can doesn't mean it's legal.
TeacherTube has a whole series of videos featuring Barry speaking about "Copyright Wisdom for Music in Multimedia." It's in 6 parts and you view can them HERE on TeacherTube. Here's the introduction: