A quick summary:
As of writing this, I have an active project called "G1 Central" which is an Android front end to the services provided by GrandCentral.com. As of Thursday, March 12th, 2009, Google has finally announced that they're going to finally be expanding this service (and, in a few weeks, taking it out of private beta), and rebranding it to Google Voice. When this happens, my G1 Central application will almost certainly stop working.
So, stop this, I have started work on a new application which is a fork of G1 Central, intended to use Google Voice as the back-end for the application. I don't yet know what to call this new application, however. The logical extension, "G1 Voice" makes perfect sense, except that I hate how I used "G1" in the name of "G1 Central"--what happens when users start getting other devices? Are they going to install an app called "G1 Central" on their G2, for example? I'd love to just call it "Google Voice", but that's obviously trademarked, and would give people the impression that it's an official app (of course, it's anything but an official app).
Regardless of what I eventually decide to call it, the new app is already making progress. I have been busy since noon on Thursday (when I got the option to upgrade to Google Voice), and the new app can make outgoing calls and load the list of voicemail. You can't yet do anything (like download or listen) with a voicemail, but progress is definitely happening at an awesome rate. Furthermore, I'll be adding SMS functionality to the new application, so you can finally send SMS from your Google Voice number!
I fully intend to make this new application open-source (Apache 2.0 license), and I expect to be making my first release early next week.