Although it's not currently available in the iOS 5 developer beta, a new leak at 9to5Mac has indicated a curious voice control feature called Assistant could be making its way into the mysterious iPhone 5 when it launches.
Sorry, "if" it launches, since there's been nothing but rumor and rampant speculation about the next version of the iPhone basically since the last one launched.
But! On to the Assistant thing that will probably/definitely be exclusive to the iPhone 5. It's based on the Siri technology that Apple acquired when it bought that company, and will do a whole lot more than just haphazardly dial contacts when you say people's names as the current iPhone does now.