Probably the best presentation I've found on copyright and fair use is Copyright for Educators from Wesley Fryer. Of particular interest to me in this presentation is the discussion of fair use practices related to using images in digital presentations. After watching the presentation you should check out Wesley's handouts that go with this presentation.
Rodd Lucier has a very good presentation about Creative Commons called Creative Commons: What Every Educator Needs to Know. In addition to this presentation, Rodd has an excellent podcast series and blog called The Clever Sheep. I encourage you to check out all of Rodd's digital content.
The Classroom Copyright Chart created by and hosted on the California Student Media Festival's website. The Classroom Copyright Chart provides teachers with clear explanations of when it is and when it is not okay to reproduce and reuse copyrighted materials. The chart can be viewed online or downloaded for printing and distribution within a school.
Another resource from the Temple Media Education Lab is this short music video about fair use.
During our Twitter exchanges this afternoon @jtheiser reminded me of the resources from the Center for Social Media at American University which includes some excellent video explanations of fair use. The video I've embedded below offers an explanation of fair use as it relates to creating remixes. In addition to the video embedded below the Center for Social Media offers documents about best practices for online video. Amongst the documents is this FAQ sheet. The Center for Social Media also offers video examples of best practices.