It's been available for iOS devices like the iPad and iPhone for some time, but now in-app purchases have been introduced for the Android platform, which is certain to be followed by a host of apps chasing your cash.Android announced the development at a press event, where it also showcased the Android Market webstore and some features of Android Honeycomb, the tablet-friendly Android operating system. But the introduction of in-app purchases is equally significant for the platform, if not more so.According to TechCrunch, Android engineering director Chris Yerga announced that developers using their in-app purchasing SDK will be able to sell virtual goods and add-ons in their apps. Indeed, the first of those games is almost ready to go - an Android version of the huge-selling Tap Tap Revenge from Disney Mobile. It's had over 50 million downloads on the iOS platform - and now it is ready for a piece of the Android action.At the event, Disney Mobile’s Bart Decrem showed how it will work, as well as noting that 25 million songs have been downloaded inside of TTR thanks to in-app purchases. So you can see the appeal to developers, especially those who don't feel they can make sufficient money on the Android platform as yet. It's also said to be very easy to integrate - Disney took five days to get a working version ready to showcase.The SDK pack is now being offered to developers, with a general launch for around spring. So expect a glut of new apps around then.