Last week Steve Jobs took the stage at the Apple Town hall meeting and announced two major things for the iPhone: 1) support for Microsoft Exchange and 2) the iPhone SDK. The Exchange support was a relatively unexpected move, but in retrospect it makes perfect sense. In order to unseat Blackberry as the number one wireless player in the US, Apple needed to have an enterprise story. What's more, Apple has realized that the days when people carried two phones are over.
With support for the enterprise (one device for both home and business use), together with its utility as a music player, camera, and web browser, the iphone is well positioned now to be that 'one phone'.