White House for Kids http://www.whitehouse.gov/kids/whlife/index.html
National Geographic for Kids http://www.nationalgeographic.com/kids/
Create math worksheets at home for extra practice http://www.mathworksheetwizard.com
Star Fall - Reading and Phonics http://www.starfall.com
Spelling Practice! Just enter your child's words and it has great activities for practice. http://www.spellingcity.com/
Fun and educational games http://www.funbrain.com/