1. A user interface for programming therapy settings of a neurostimulator having at least one stimulation lead implanted within a patient's body, each lead having a plurality of electrodes, the user interface comprising: a stimulation zone-programming interface that is at a first level of abstraction and that graphically displays, and allows a user to specify treatment parameters for, at least one idealized stimulation zone; a field strength-programming interface that is at a second level of abstraction lower than the first level of abstraction and that graphically displays, and allows a user to interact with, at least one modeled electromagnetic field strength representation corresponding to the at least one idealized stimulation zone; and an electrode-programming interface that is at a level of abstraction lower than the second level of abstraction and that displays, and allows a user to interact with, electrode settings.