Aviator's Guide to GPS
   Get a feel for using digital readout and moving-map GPS receivers with this book's unique, fully illustrated examples that is devoted solely to GPS navigation.
   http://www.amazon.com/exec/obidos/ASIN/007011546X

Fugro SeaSTAR
   Differential GPS for oceangoing vessels.
   http://www.fugroseastar.com/

Handheld GPS in the Cockpit
   Information on using hand held GPS units in the cockpit addressing issues such as navigation, aviation vs. non-aviation units, where to get waypoints and other relevant topics.
   http://www.cockpitgps.com/

Pacific Coast Avionics.
   Authorized avionics distributor of GPS, autopilot, and other aircraft instruments.
   http://www.pacific-coast-avionics.com/

Porcine Associates
   Couplers that allow connection of hand-held or panel-mounted GPS receiver to autopilot. Follow a GPS course or hold a heading.
   http://www.porcine.com/