For the past month or so, hints and clues about Google Talk opening up have been flying back and forth. People spotted DNS SRV records for the gmail xmpp servers and there's been a lot of frenzied speculation about what and when Google is planning. (You may recall I discussed this previously)
Today it looks like things have opened up considerably more. The Google Talk servers are now doing successful outbound traffic to the wider world of the XMPP/Jabber network. Google Talk users are able to add non-gtalk Jabber address to their contact lists, and in many cases it's working great. Some friends report successful invite and message passing between the Google Talk servers and their own, personal Jabber servers.
I'm having less luck on my end, though, and I can't quite tell if the problem is local or systemic. I'm receiving traffic from the Google servers without any problem, but any time my jabberd server (release 2.0s10) tries to send messages back the connection breaks. The logs aren't all that useful, but I'm encouraged. dbaker's jabberd v1.4 server is failing in a similar way, but one particular server that is working is also a 1.4.3-3 server, so I don't think it's a fundamental jabberd problem.
Update 7pm CST: I gave up on jabberd and migrated to ejabberd. Connectivity with Google's servers is working for me now. Curiously, it appears as if Google has chosen to not (yet?) implement s2s encryption. The google servers appear to only do callback verification on s2s traffic. Don't get me wrong, though, I'll take what I can get. This is a huge win for instant messaging consolidation. Way to go, Google!
What this means for us is that there's now a viable, well-supported, mainstream IM solution for end users. There's a Jabber solution now that you can recommend to your mom, or your boss, or your kid sister. Heck, most of them are already signed up to use it as a byproduct of their Google Mail account. They can connect to their Google Talk accounts and chat freely with the bearded suspender-wearing unix fossil community who are running their own private Jabber servers. They can connect to the thousands of businesses and organizations in the world that run their own internal-chat Jabber servers. They can connect to me, and you, and anyone else who has embraced open instant messaging. This is going to be big. Just wait until AIM gets absorbed next.
Update 9pm CST: If you're seeing the same dropped connections that I was getting with jabberd2, you might want to take a look at this bugzilla entry which claims to have a (simple) solution to the problem. Apparently Google's servers are particularly strict regarding the xml namespace of messages and jabberd is particularly loose. Worth a shot.