Single sign-on is at the heart of today's Facebook announcement, and Zynga Poker is first on board -- and is coming to Android. You can see in the blurry screen shot above that there's a big "Login with Facebook" button. And that's how it'll work. You'll be logged into Facebook on your phone, then just tap that button in other apps. And in addition to Zynga Poker, these apps were announced as early adopters:
And undoubtedly, more will be on the way.