Amazon's single sign-on launched for Kindle Fire three weeks ago, and as of today it's now available on more standard Android-based devices. The straight-forward Amazon app available in Google Play has been updated to support the single sign-on service and integrates with Amazon's other apps for Android. Sign in with the Amazon app and your other Amazon services apps on your Android device will also be logged in.
Single sign-on through Amazon only works with Amazon's own apps, and only on devices running Android 2.3 or higher. The app also has gained a new icon that fits in with the more modern Android interface, instead of the older pseudo-3D gradient icon it used to have.
The Amazon for Tablets app hasn't yet been updated with Amazon single sign-in, but we imagine that's only a matter of time.