1. A three-dimensional user interface system, comprising: at least one pointing/input device; an imaging device configured for capturing a plurality of sequential image frames, each of the image frames providing at least two different views of a scene comprising the at least one pointing/input device; and at least one computer program product operable on a computing device having at least one processor, at least one memory, and at least one graphical user interface; wherein the at least one computer program product includes executable instructions for calculating from the plurality of sequential image frames at least a spatial and a velocity parameter of the at least one pointing/input device when moved through a three-dimensional space, and for rendering, on the graphical user interface, a visual marker corresponding to the spatial and velocity parameters of the at least one pointing/input device in three-dimensional space.