Funschool math games http://funschool.kaboose.com/parent-teacher/5th-6th-grade.html
Multiplication.com Math Games http://www.multiplication.com/interactive_games.htm
Learning Planet http://www.learningplanet.com/stu/kids3.asp
funbrain http://www.funbrain.com/index.html
prongo math games http://www.prongo.com/games/ages9-12.html
gamequarium http://gamequarium.com/geometry.html