Useful sites for teachers: Biology

Concord's High School Biology Resources provides visual simulations for teaching science to high school students

Biotech-Adventures: an educational web site designed to present the factual information regarding biotechnology in a way that will entertain both students and adults.

The Missouri Botanical Garden has quite a nice site on biomes and ecosystems

Understanding evolution is a website for teachers, aimed at explaining evolution, pointing out relevance, misconceptions, pitfalls, and so on.