[Air-l] Available Chat/IM Tools?

Dear Colleagues: I am setting up an Illinois standards-based sports safety/science TV show and website for K-12 students. I would like to include chat and instant messaging as a component. The concept I have in mind is to use a website as an "after the show" vehicle for kids, teachers, parents, etc., to converse with afterwards. Does anyone on this list have info as to good tools that are available for low/no cost? Thanks, Matthew Newman Executive Editor Sports Smarts msjanew@aol.com