BRAINPOP.COM
Pretty cool. Terrific interface. Instruction, content, production values all excellent.
Numerous awards and significant partnerships. Good model. Has a lesson for each item on the standards list.
Linked with McGraw Hill and other key organizations.
Good section on special needs kids like dyslexia and autism.

Sparktop.org http://www.sparktop.org/explore/brainpop.html Linked to Brainpop. Site for dyslexia and LD sponsored by the Schwablearning.org of Charles Schwab.

Academic Benchmarks. com. You should know if you don't already. Useful tools for matching your curriculum to national and state standards item by item. Clever business idea.

Useful listing of educational sites (that all happen to use Academic Benchmarks.com)
Acahttp://www.academicbenchmarks.com/partner/