Instead, why not use the technology that Google uses at its core, in its original, unhampered beauty? Its XMPP, otherwise known as Jabber, and it is THE open-source, xml messaging technology. It's free, and it's cool. There are a bunch of clients from which you can choose, and it works a little bit like IRC, in that you can have a lot of different servers to choose from, but they can all exchange instant messages between them. This makes it a much cooler way of doing things than the central control which Google can lord over you.
Since so many people seem to be making the swap these days, I wanted to see if I couldn't get all of my friends over to the Jabber side of things, and that way we could all talk with even more freedom, and we wouldn't have to worry about things like AOL or Google taking over our lives.
Pandion Client -> A good client
Psi Client -> The client I use
Spark IM Client -> The client I might use
Exodus Client -> "The" windows client
Gush Client -> The prettiest client, probably easiest to use.
And for anyone who is interested in group chat sessions, or who prefers the more traditional ways of chatting, I run an IRC channel on DALnet called #sacrideo. If any of you want to chat with me, that is a great place to do it. I try to stay on their pretty often, and I really like to chat on IRC more than any other service. If you can manage it, and you feel like dropping by, definitely do. For those of you who were used to my old channel !sacrideo on IRCnet, you should know that the servers have changed, and you should be attempting to connect to DALnet not. The server I like to use is jade.va.us.dal.net.
So yeah, I know a lot of you don't do the whole chat thing, but for those of you who do, I would really encourage you to give Jabber/XMPP and IRC a chance. My nickname on IRC is arcfide, and my current Jabber ID is firstname.lastname@example.org.