Geography for Kids - This site is under science because it has information on the atmosphere, weather, climate and geology. There is a video on most every page to go along with the information.
Maps4Kids - This is a good site for state information, information of every country on earth, fun facts and mapping games.
Atlapedia - This site shows maps two ways, both regional and political (looks like a relief map). The countries are also listed alphabetically which is a nice feature. When you find the country you are looking for, you will find detailed information!
GeoGames - This site is full of geography games that students can play individually or even as teams on the smartboard. They can build maps by dragging and dropping and when they are done, the map can be printed! There are tutorial videos for you if you get stuck!
World Fact Book - This site was created by the CIA and is better for the upper grades. Great information written on a higher reading level. There is also a kids zone where the students can explore and learn about the CIA!