Bah, I dunno why, but I accidentally found this site called conforums.com and there you can make a website that's like these forums and I went on a few, and most of them have chat rooms. I dunno if there are a lot of people on though.
Anyways, I'd check with disney, because kid-friendly chatrooms (outside of chats that are private, such as AIM and MSN)are hard to come by. Unless the parents and whatnot are fine about cussing ( I recommend runescape btw, their censor system is really hard to get past)