Cool Classroom Demos: From a potato battery to a rose with dissapearing color. This site has some great grabbers.

Mad Scientist Library: A great general science site with many experiments and in formation in all areas.

Beakman and Jax: Asked a question you can't answer, give this site a try. Many interactive demo's make this site a lot of fun.

Chemistry Exam Exchange: Over 40 tests, exams  and quizes ready for downloading.

Chemistry Teaching Resources: Organized by educational level. Provides a good breadth of materials for teachers.

Bizzare stuff: Experiments you can do in your kitchen (mostly). Some of these activities can be dangerous but all are ranked for safety. Many very good labs and Demos.

Flinn Scientific: Chemistry and biology demonstrations and information.

The Catalyst: Developed for high school chemistry teachers to aid in finding information of value in instruction.

The Periodic Table: This site provides a huge amount of information about every known element

ChemTeam: An online tutorial for secondary chemistry broken down by topics.