Graphical knowlege engine
Similarity search engine for English Wikipedia. Finds related pages.
Well organized, attractively presented site
Searchable resource library. Includes lesson plans.
Amazingly simple tool for instructors
For teachers and students
Compare Bing, Wolfram, Wikipedia, Delicious, Stumbleupon with Google side-by-side, get the best of these very different search engines, content providers, and social bookmarks
Free, professional development resource that helps educators and librarians address common questions about the use of technology in teaching and learning by providing easy access to practical, online resources and activities.
Ask questions - get live answers from your friends (and their friends)
Huge list of free ebooks