Education 4 Kids
http://www.edu4kids.com

Figure This
http://www.figurethis.org

Math Stories
http://www.mathstories.com/

AAA Math for Kids
http://www.aaamath.com/

Math Playground
http://mathplayground.com/

Create a Graph
http://nces.ed.gov/nceskids/createagraph/default.aspx

Kid Sites
http://www.kidsites.com/

Surfing the Net with Kids Math
http://www.surfnetkids.com/directory/Math/