An agile optical scanning scheme is proposed that uses wavelength manipulations for deflecting a free-space optical beam by selection of the wavelength of the light incident on a wavelength dispersive optical element. Using fast tunable lasers or optical filters, this scanner features microsecond domain scan setting speeds, single/multiple beam(s) in space, and large several centimeters or more diameter apertures for sub-degree angular scans. The beam scanning scheme offers simple control (via wavelength tuning). The paper also introduces space multiplexing for optical beam scanning and discusses various system architectures utilizing both space and wavelength multiplexing to achieve high speed optical scanning with coarse and fine tuning capability. Experiments described demonstrate high-speed, high resolution, wavelength tuned optical scanning in one-dimension (1-D), two-dimensions (2-D), and three-dimensions (3-D).