The following links have been passsed on by teachers -
This one is a science site - lots of interactive things and powerpoints - be careful though - it's a UK site and the vocabulary and math are often different - still some good things to check out
http://www.aasd.k12.wi.us/staff/boldtkatherine/ScienceFun_K-3.htm
Worksheet website - specifically good maps for GAA level students: This site is free right now but will soon have a subscription - look at it and save your resources now.
http://www.worksheetworks.com/
Free site right now - in BETA - will have fee soon - check it out now while it's free:
http://www.helpkidzlearn.com/
Another site for Frozen Waters or biomes (tundra) : http://beyondpenguins.ehe.osu.edu/stories-for-students#dinosaurs Has different reading levels