You Tube Space Lab (with Bill Nye) - http://www.youtube.com/user/spacelab?feature=watch
NOVA Education - http://www.pbs.org/wgbh/nova/teachers/
Discovery Science Education - http://www.discoveryeducation.com/administrators/curricular-resources/science/index.cfm
National Geographic for Kids - http://kids.nationalgeographic.com/kids/
Environmental Protection Agency - http://www.epa.gov/students/
NASA for Students - http://www.nasa.gov/audience/forstudents/index.html
Periodic Table - http://periodictable.com/index.html
Kids' Health - http://kidshealth.org/kid/
Kids Do Ecology - http://kids.nceas.ucsb.edu/
Weather for Kids - http://www.weatherwizkids.com/
Timed Science Games - http://www.purposegames.com/games?t=744&so=mp