1. A method for configuring a human interface and input system for use with a host hand-held electronic device configured to run applications, wherein at least one of the applications is associated with multiple input functions, the method comprising: selectively disposing on a first surface of the system a first input assembly having input elements configured to receive input from a human user through manipulation of the input elements, wherein at least one of the input elements of the first input assembly is further configured to map to one or more of the input functions associated with a selected one of the applications; selectively disposing on a second surface a second input assembly having one or more input elements configured to be manipulated by one or more of the human user's fingers, wherein at least one of the input elements of the second input assembly is further configured to selectively map to one or more of the input functions associated with the selected application; and selectively arranging the first input assembly and the second input assembly in substantial opposition to each other.