Macrumors has been digging through Apple patents and found some very tantalizing nuggets of perhaps possible future iPhone features. 

Fingerprint identification using fingerprints to identify each finger and associate actions based on each finger.  This would allow the iPhone to interperet each finger action seperately, allowing for easier and more acurate control over input by the user.

Haptic feedback Not just "touch the screen and get feedback when you hit a key".  That’s too easy.  Apple’s plan is to have a "grid of piezoelectronic actuators that can be activated on command. By fluctuating the frequency of these actuators, the user will "feel" different surfaces as their finger moves across it. As an example, a display could include a virtual click wheel which vibrates at a different frequency as the center. Users could easily sense the difference and use the click wheel without having to look at it."  Dayum, that would be cool.

RFID reader built into the screen?  We’re not quite sure why they’d need to do this (as opposed to putting the reader somewhere else in the device) but Apple has put a patent application on this.