Great resouce for children's literature applicable to math lessons. You can search by grade or topic. The site also has links to some lesson plans and online activities which go with some of the books.
The NCTM website has excellent ideas for lesson plans, interactive on-line math activities, challenge problems, and more. NCTM offers many professional development resources such as journals, on-line conferences, information about regional conferences, an
Highly respected site with great resource for teaching internet safety particularly for middle school and high school students. Divided into short units which must be done in sequence. Includes short videos for classroom use.