This gives lots of information about subjects in our past reading series. http://www.mhschool.com/reading
National Geographic for Kids http://www.nationalgeographic.com/kids/
math practice and games http://www.Aplusmath.com
Enchanted Learning - most anything you're looking for http://www.enchantedlearning.com
math baseball, spelling games http://www.funbrain.com
kids' educational games http://www.kidsdomain.com
lots of everything http://www.abcteach