Hi-Z Technology Inc. http://www.hi-z.com/
Manufacturers of power generating modules, systems and materials. Includes technical specifications and scientific publications.
JPL Thermoelectrics http://www.its.caltech.edu/~jsnyder/thermoelectrics/
Comprehensive information source about the technology and its applications from the Jet Propulsion Laboratory (JPL) of the California Institute of Technology (CALTECH). Includes history, scientific background, and device overview with animated illustrations.