Google chat in gmail

You can now chat from within the gmail interface (so no need to open another program) - or at least you can if your contacts also have had this feature enabled in their gmail account. My first gmail account has had this option enabled but my main google account that I use on a day to day basis (as it contains all helsby.net emails) does not have it activated yet. The strange thing is that you can initiate a chat invite from a working account (and I was hoping that would activate my secondary account for chatting) but the secondary account does not receive the invite in the mail box - I'm guessing it probably goes to the chat client - if it has been downloaded.
It will be interesting to see how this progresses. At the moment I'm guessing it is text only IM similar to the web interfaces to MSN and ICQ.
In related news I've been setting up a Live Communication Server for a client and the Communicator program looks pretty good. The annoying thing is that I can't see any documentation on how to get hold of the non-trial version of the client - it apparently is free with licences for the server so you would expect to get the media for the client with the server - but nooooooo.......