1. An external control device for use with a neurostimulator coupled to a plurality of electrodes capable of conveying electrical stimulation energy into tissue in which the electrodes are implanted, comprising: output circuitry configured for transmitting sets of stimulation parameters to the neurostimulator; a user interface including a display device, wherein the user interface is configured and arranged to display a programming screen on the display device, wherein the programming screen comprises a first control element configured to be actuated by a user to selectively place the external control device in either a pre-programming mode in which changes to stimulation parameters are not transmitted to the neurostimulator or a live stimulation mode in which changes to stimulation parameters are transmitted to the neurostimulator using the output circuitry and the neurostimulator stimulates the tissue using a current set of the stimulation parameters, wherein the programming screen further comprises a second control element configured to be actuated by the user to change a stimulation amplitude and a third control element configured to be actuated by the user to select at least one stimulation electrode; and a processor, when the external control device is in the pre-programming mode, configured for simulating a volume of tissue activation using a computational modeling technique for each of one or more candidate stimulation parameter sets, while preventing the output circuitry from transmitting the one or more of candidate stimulation parameter sets to the neurostimulator.