1. A system for visually guiding a flexible endoscope through linked passages within a body, comprising: (a) a signal source that emits a reference signal useful for spatially tracking a progress of the flexible endoscope through the linked passages; (b) a sensor that produces an output signal indicating a three-dimensional disposition of a distal end of the flexible endoscope using the reference signal of the signal source; and (c) a display for displaying a view from within the linked passages as the flexible endoscope is advanced therethrough, to enable the flexible endoscope to be visually guided and tracked along a path followed through the linked passages.