Boku makes one-tap billing available on Android in 56 coutries
The pay model in many mobile apps, and especially mobile games is increasingly moving to a freemium model where apps are free to download, but have a lot of extra content that can be "unlocked" for a fee. Mobile OS makers have begun offering in-app purchases using the same payment system as the respective app stores, only Microsoft has yet to include in-app purchases. Boku wants to work around those systems, and has launched an Android SDK and support in 56 countries.
As you can see on the map, Boku supports 56 countries throughout the world, including 32 languages and 40 currencies. Boku is compatible with Android 1.5 and up, so that means there shouldn't be any unsupported devices.