Biology In Motion http://BiologyInMotion.com
Online activities for learning biology, including animated cartoons, an evolution simulation laboratory, and drag-and-drop quizzes.
The Dolan DNA Learning Center http://www.dnalc.org/
A wide variety of online DNA resources as well as information on many workshops, field trips, courses, and products - from the Cold Spring Harbor Laboratory.
Mr. Biology http://www.sc2000.net/~czaremba/
Practice tests, simplified explanations of hard to understand concepts, teacher help, and links to exciting web sites for teaching & learning High School Biology.