Energy, Machines, and Motion bibliography

About.com
On this site, you can ask an expert for help with a question or search a variety of links for yourself. Very user friendly!

Ask Eric
This site provides access to a wealth of information about any subject. Easy to use and works basically like a search engine for a giant encyclopedia.

B. J. Pinchbeck's Homework Helper
This site was developed by an 11-year-old student and his dad to help students with their homework in any subject. Includes an impressive list of links -- especially for the sciences.