TechTV just yesterday released the newest iteration of their chat, and it is quite a nice system. They decided to run Jabber on an in-house server. This is likely a wise decision due to their problem in the past with proprietary chat services.
The default and preferred method of connecting to their chat system is through their Java Jabber applet, but it is possible to connect to their server with a standard client. I will not reveal those details here, in case TechTV does not want those released, but it makes it nice to use TKabber under Linux, where Java support can get a little hairy if not set up properly.