Overall U.S. government site on copyright, if you want to know the law and the history of it, this site has it. It is not overly complex or hard to understand. http://www.copyright.gov/

A U.S. government site with an explanation of fair use:  http://www.copyright.gov/fls/fl102.html

A very readable blog explaining public domain:  http://blog.ebusinesslawgroup.com/2008/11/are-works-youre-usingreally-in-public.html

This site consists of a great chart on public domain that contains the specifics about a wide variety of the dates and types of materials and when they fall into public  domain:  http://www.copyright.cornell.edu/resources/publicdomain.cfm

An excellent summary of what is and isn’t correct on the web as related to copyright: http://mason.gmu.edu/~montecin/copyright-internet.htm

Good article about copyright for educators, but with excellent comments on teaching morality: http://www.goehner.com/copyright.htm

The site that explains creative commons and links to its search function:   http://creativecommons.org/

Video tours of free image sources and online webinars of how to use and modify the images:  http://www.effectivechurchcom.com/category/skills/clipart-how-to/