White House for Kids http://www.whitehouse.gov/kids/whlife/index.html
National Geographic for Kids http://www.nationalgeographic.com/kids/
Kid's Health http://www.kidshealth.org/kid
Funbrain (fun games for math, reading, etc.) http://www.funbrain.com
Study Island http://www.studyisland.com
Kid's Discovery http://kids.discovery.com