Fun sites for kids: 

http://www.starfall.com :  Early literacy web site with activities from letter recognition and sounds to early reading.

http://www.literacycenter.net/lessonview_en.htm# :  Learn your letters, numbers, colors and shapes.

http://www.uen.org/k-2interactives/abc.shtml :  ABC games for Kindergarten through 2nd grade.

http://www.uen.org/k-2interactives/listening.shtml :  Listening activities for Kindergarten and 1st grade.

http://www.uen.org/k-2interactives/reading.shtml  :  Reading activities for Kindergarten through 2nd grade.

http://www.uen.org/k-2interactives/writing.shtml :  Writing activities for 1st and 2nd grade.

www.emgames.com : Math games from K-5