Starfall
White House for Kids http://www.whitehouse.gov/kids/whlife/index.html
National Geographic for Kids http://www.nationalgeographic.com/kids/
Fun activities - by girls....for girls. http://www.missoandfriends.com/
BBC for kids math, science, and English practice in game format http://www.bbc.co.uk/schools/ks2bitesize/
Arthur games and activities http://pbskids.org/arthur/
Games and activites with the author Kevin Henkes http://www.kevinhenkes.com/
Math Patterns, logic and more http://www.learner.org/teacherslab/math/patterns/index.html
Practice with telling time and more http://www.cartooncritters.com/Time.html
Magic School Bus, need I say more? http://www.scholastic.com/magicschoolbus/games/bugs/index.htm#
All subjects http://www.linkslearning.org
Place value practice Place Value
Math Practice (organized by skills)