Siri, the voice activate assistant in iOS 5, is disabled default.To enable Siri for use go to Settings | General | Siri. Once enabled just raise your phone to your face and speak a command. If your are not aware Siri is only available on the iPhone 4S. There is no doubt the jailbreak community is looking to bring Siri to other iOS devices however for most people you will need to buy and iPhone 4S to have Siri. The functionality is fantastic and natural. It is a novelty currently but over time it remains to be seen if this will be something we want to use of if this will become that feature that should remain disabled. 
