Reports are that Google, a recent entrant into the messaging and voice arena is going launch a "federation" that will enable the messaging and voice players to be interoperable with one another.
Expect to see the likes of the SIP crowd in it. My guess is that SipPhone will be one of the first to jump in the arena. The big question is will Yahoo or Skype be a party to the play?
Update--Earthlink has piped up and told me also that they are the first ISP to collaborate with Google to open up its instant messaging and voice communication product.