It’s a very common issue in the yearbook world: what falls within your “fair use” rights and what is absolutely forbidden? Here is a very cute video–made entirely from Disney clips–that explains it.
Disclaimer: the rhythm is a little challenging, so you might want to have a student sit down and transcribe the soundtrack and then hand that out to the whole class when you show it.
http://www.youtube.com/watch?v=CJn_jC4FNDo
(Thanks to Eileen Chang at Terman Middle School for sharing this with me!)