starfall.com is a great way to reinforce vowel sounds http://www.starfall.com
Books and Fun http://www.scholastic.com
Ask Jeeves for kids! http://www.ajkids.com
Jan Brett's Website http://www.Janbrett.com
Find your favrite author and read about him or her http://www.kidsread.com
social studies http:www.timeforkids.com