MacRumors points us to AT&T’s new ‘Upgrader App’, that lets users pre-order the iPhone 4S directly from their iOS device (due out on the App Store later today). It lets you pre-order right from your handset starting Friday, October 7. Besides actually performing the evil deed of purchasing the darn thing, the app lets users know their upgrade eligibility and how much the iPhone 4S will cost them.

We’ll update when it goes live.