Ok, this is not strictly related to copyright, but is pretty cool and you should know about it. Pearson education and Google have teamed up to make math videos available to the masses. You can link to these videos from your website or blackboard classroom and have the ability to provide great content that is no work for you. What could be better?
Well, it could be better if it were all free - students can purchase the lectures for 99 cents to $3.99 for lectures and textbook chapters. There are some free lectures available as well.
These kinds of lectures can be especially useful for folks who have math components in their non-math classes and need some way for the folks who need extra help to get it without taking up class time.