The Google Charts API supports creating good looking formulas based upon LaTeX input:
Does someone know an online chat service which makes use of that API to display discussed formulas, maybe with the use of editor such as seen in Knol?
Web Applications Stack Exchange is a question and answer site for power users of web applications. It only takes a minute to sign up.Sign up to join this community
I personally use MathIM, which is an online chat room which parses everything between
$$'s in your message as TeX. It's perfect for talking to my friends when I need to use math equations.
It seems to be exactly what you are looking for :)
You can try Pidgin (http://www.pidgin.im/) is an IM client for windows, MacOS and Linux. Then install this pidgin plugin: pidgintext
GmailChatTeX may work for you.