To access the chats, choose either then General chat area or the Special chat area. There is a choice in each of these to register. Then you have access. In the general chat area, I think that most of the homeschoolers hang out in the Mom's Place Forum. PrestonSpeed Publications offers several chats including one for the kids.
Family now has a homeschooling chat.
This is really an IRC chat that you can get to through their web page. Although the room is always open, there is a scheduled chat Thursday mornings at 7am pacific time. UNschool Chat is a java based chat for homeschoolers.