Hidden in the code of the latest iOS 7 beta release is information about some likely new features for the next iPhone. Specifically, the beta 4 includes a folder called BiometricKitUI that alludes to a fingerprint scanner in the iPhone's home button. At this point, it appears the scanner will be able to unlock the phone, but it's less certain if the biometrics will enable mobile payments.
If Apple makes an API for the fingerprint scanner available, that would definitely be of interest to the mobile development community. Enterprise apps, in particular, would benefit from the enhanced security provided by biometrics.