Google took some subtle shots at Apple, including showing a drawing of an Android mascot eating an apple. But Google Vice President Vic Gundotra said, "We were just having a little bit of fun, we try not to take ourselves too seriously. We're all doing really amazing work. It's great to be in a battle for the hearts and minds of developers."

Google is making a bigger push into the online music and movies markets where Apple has been so successful with iTunes. At Google I/O, the company announced a new music service that lets users stream music from the Internet or cache some songs for offline play on Android devices and PCs. Google also said it is bringing movie rentals to the Android Market, starting at $1.99 for a movie. The movie rental service went live today and the music service is in a limited beta.

Google also showed off some functionality coming for tablets that will let developers build new types of applications. One included a camera that reacts to movements of a person's head and eyes, and can recognize two people and switch perspectives based on who is speaking. Another technology lets users control remote objects with their tablet's movements, for example a game where you move a metal ball around a maze with a series of holes.

Google showed off future technology where the Android device will become a control mechanism for any electrical object in the home. Light switches, dishwashers, anything could be controlled by the Android device, and developers could build applications that integrate with this functionality. A stage demonstration showed a Google employee playing the first-person shooter game Quake on a tablet, with game actions such as shooting enemies also turning lights in the room on and off.

Functionality in the just-released Android 3.1 includes a larger Gmail widget to view more messages, multitasking that automatically shuts down and restores applications automatically, and the ability to connect with USB devices, including digital cameras, keyboards and game controllers.