Chemistry Education Resource Shelf - This site provides high school and college-level chemistry educators with various teaching resources, including a comprehensive index to chemistry textbooks in print. Subjects covered range from Biochemistry and Computers in Chemistry to Quantum Chemistry and Writing in Science.
The Catalyst - This site has been developed for the high school chemistry teacher. Site can answer chemistry questions, allow teachers to post their ideas & insights, provide lesson plans and maintains links to other interesting chemistry pages.
Chem4Kids - The site is designed to introduce basic chemistry ideas to younger students, but anyone can use it. Most of the content relates to the Periodic Table.
Doc Brown's Chemistry Clinic - A growing non-commercial general help and revision site for GCSE, AS and A2 CHEMISTRY but should be of use to USA/Canada grades 9-12 students. Revision notes, multiple choice tests, structured questions, graphics and extensive links to useful and interesting CHEMISTRY sites. One site speciallity is the structure and naming of organic compounds.

 

Food Science: Cook & Eat Chemistry - A curriculum guide that links chemistry and food preparation. The chemical composition of food is a neat way to explore chemistry. This site has lots of information and tons of lesson plans/guides!
It's Elemental - The computer will give you an element and you have to supply either the element's name or it's chemical symbol. Press the 'Check my answer' button after you have entered your answer.
Linus Pauling Virtual Exhibit - Check out a very well presented and educational exhibit of the influential scientist's life and contributions to science.
Model ChemLab - Whether your challenge is to introduce new computer technology to your curriculum, or bring the lab experience to on-line students or a need for an alternative to dangerous, expensive or environmentally hazardous labs, then Model ChemLab is the classroom prove solution for you. ChemLab comes with a range of pre-designed lab experiments for general chemistry at the high school and college level.
Molecular Modeling - Mathematics and Molecular Modeling, from NYU. Their Quick Tour is particularly nice for high school students.
Mr. Guch's Cavalcade o' Chemistry - A resource for high school chemistry teachers and students. There are lesson plans, sample homeworks and tests for teachers. For students there is a helpdesk, tutorials, and a reference area.
RasMol: Molecular Modeling Software - Free software for Windows, Macs, Unix and VMS which shows 3D images of molecules, especially biological macromolecules such as proteins and nucleic acids. A gallery of images is also available at this site.
Temperature Conversion Calculator - Conversion to and from several temperature scales.
Adrian Dingle's Chemistry Pages - Wonderful GCSE, A level, AP, high school honors and regular chemistry resource.
ScienceSoft - Develops software for scientific purposes.