Technology & Learning has a helpful article on Dealing with Copyright. As teachers are responsible for helping these media savvy students to understand and follow copyright guidelines, this quick guide to copyright will be of assistance. The guide also covers using Creative Commons licensing. For those unfamiliar with Creative Commons licensing, it allows students (and faculty) to use content (such as images) for free, or free with attribution, or in other ways designed by the person who created it.

You can check out the article here:
http://www.21centuryconnections.com/node/302