In what may kick off a financial boom for Android developers, Google said today that in-app billing will finally roll out to consumers next week. The feature, announced in January, has been in beta for the last two months.

Google’s in-app billing comes at a time when mobile developers are moving away from paid apps to free ones selling virtual goods; nearly half of the top-grossing apps on iOS are now free. But Android developers have yet to offer in-app purchases because Google has delayed the launch of in app billing for several months. Coupled with Android’s exploding market share, next week’s launch may jump start an era where developers start to earn more on Google’s platform than on Apple’s. Rovio Mobile, the Finnish developer that makes Angry Birds, told us recently that its Android revenues now roughly match iOS.

Developers can now upload and do end-to-end testing of their apps in the marketplace, in addition to crate product catalogues and set prices. They will be able to test live transactions as if they are real users.

While Google will handle payments and fraud, developers will need to store and deliver their digital content and handle refund requests.