Fun Sites:

Disney Online
Disney Junior
Cartoon Network
Nick Jr
Nickelodeon
PBS Kids
Sesame Street
Sports Illustrated for Kids
Club Penguin

Fun With Math
Cool Math
Math Playground

Fun with Language:
Poisson Rouge

Fun With Music:
New York Philharmonic KidsZone
Playmusic.org
SFSkids.org
PBS Kids Jazz
KIDiddles

Fun With Reading:
SuffolkWeb's Fun with Books

Fun With Science:
The Yuckiest Site on the Internet
Space Place

Online Games:

Prongo.com
Funschool.com
PrimaryGames.com
Funbrain.com
DisneyXD Games
Playkidsgames.com
Jump Start
MoshiMonsters
Polly Pocket
Flat Stanley