Encourage your students to use digital cameras and camcorders to shoot their own pictures and video, create their own charts and graphs with software such as Microsoft Excel, search for copy-right-free music on the web rather than use commercial songs, and in general, think about how to create a digital story that uses as many copyright-free materials as possible.
You can find more information about copyright and educational fair use at the following websites:
Legal Music For Videos - Creative Commons
Dafont 100 free fonts
Clkr (public domain clipart)