According to Techcrunch, Google is in discussion with Grandcentral, a company that gives out one Central number that forwards to any number of phones you already have, making you available by phone on just one number.
It will most certainly be a great addition to your googlephone....

I'm speculating on where Google will use GrandCentral, but the synergies with Gmail and GTalk are fairly obvious and could be the next step in Google's competition with Skype and other instant messaging platforms.(TC/Michael Arrington)

I couldnt have said it any better. I also agree on the fact that this might be Google's smartest move ever. It will certainly turn google in a communications giant.