There are many very good websites that provide a wealth of information on GPS, these are just a few.

If you really get interested in GPS you may want to join the Institute of Navigation (ION)   http://www.ion.org/

There is even a magazine devoted to the subject of GPS called "GPS World"  http://www.gpsworld.com/

Link to Zarlink for chipset specs                          http://products.zarlink.com/partfinder/prodprofile.cgi?device=675

Link to Dan Doberstein's company that offers a single channel hardware GPS receiver  http://www.dkdinst.com/

Link to the university of Colorado  http://www.colorado.edu/geography/gcraft/notes/gps/gps_f.html

Link to NavTech which sells GPS related books and GPS receivers http://www.navtechgps.com

Link to the US Coast Guard for GPS related information http://www.navcen.uscg.gov/gps/default.htm

Link to Sam Wormley's GPS page http://www.edu-observatory.org/gps/tutorials.html

Link to Peter Bennett's GPS page http://vancouver-webpages.com/pub/peter/

A link to my friends at the GPS JPO http://gps.losangeles.af.mil/

A link to the proposed European GNSS Galileo http://www.galileo-pgm.org/

A link to our Russian friend's GLONASS system http://mx.iki.rssi.ru/SFCSIC/SFCSIC_main.html

Link to SNAP - Satellite Navigation and Positioning Group at UNSW http://www.gmat.unsw.edu.au/snap/snap.htm

Doug Baker's company GPS Creations for GPS hardware for running OpenSourceGPS http://www.gpscreations.com/