Simple Machine quizzes and activities http://edheads.org/activities/simple-machines/
Simple Machine info. and quiz http://www.coe.uh.edu/archive/science/science_lessons/scienceles1/finalhome.htm
http://www.smartown.com/sp2000/machines2000/main.htm
An interactive site about Simple Machines http://www.cdli.ca/CITE/machinessimple.htm