Mobile App Business Extra- App Inventor for Building Android Apps
App Inventor uses a web browser for your app design and Google stores your app development work on their servers free of charge. Using App Inventor to add functions is like using building blocks, and you can see your app on your Android device, or in the Android simulator on your computer as you make changes.
Using App Inventor only requires using the App Inventor Designer (on the web site) where you select components for your app, and the App Inventor Blocks Editor, where you literally drag, move, and drop the components to determine how they behave. A free download works with Mac osX, Windows, and Linux operating systems.
MIT announced that their public App Inventor service will be available by the end of the first quarter of 2012 and is making code available for schools to host their own App Inventor Web sites.