FunBrain.com
This site contains many great educational games such as Math Arcade, Math Baseball, Proton Don, Grammar Gorillas and more!
FactMonster.com
A seemingly endless amount of information about all kinds of topics like geography, history, science, people, etc.
www.internet4classrooms.com
Lessons and study aids organized by grades.
"Train up a child in the way that they should go: and when they he is old, he will not depart from it." Proverbs 22:6 KJV