there is a website called Brainnook where kids get to have friend and chat with them under a guideline also they get to play math and language games.
scholastic is one of the best websites
A good website for girls (kids) is gamesforgirls.com
KidzSearch.com is a good resource for kids websites.
bered.com
4leaf.tk is the best social network ever just for kids. You can create a blog, enter contests, chat in chat rooms, comment on profiles, have your avatar, and more
Kids world .com
imvu.com is a good one
Fantage is a good one.
Clubpenguin
scary for kids
neopets
Why not try gamesforkids.com