As you may have heard, Google Talk is up. The client looks neat and all, but there's not much reason for most people to start using it. Sure, the voice chat thing is neat, but I know that Yahoo Messenger supports it, and probably some of the others do? Otherwise, the client seems awfully thin. Simple, like Google, but it needs to be a lot more than that to make a difference.
Interesting thing about the service itself is, it's actually seems to be just a server running the open source jabber protocol. Since it's jabber, you can have more than one client on without knocking the other offline. (Am running both google client and GAIM right now) This means, if you leave your PC on at home all day for some reason, at work you can still log in to Google Talk without knocking the home login off the server.