Peter Bennett's FTP directory -- excellent GPS site: programs, FAQ, information.
GARMIN Web site!
Landings aviation hub -- I like their weekly newsbrief that you can subscribe to for free.
AFRCC (Air Force Rescue Coordination Center)
Aircraft Owners and Pilots Assocation
FAA -- Federal Aviation Administration
PC Software -- Many free PC Programs from the government.
TIGER Home Page -- They have some US datafiles
Directory of ftp.blm.gov/pub/GIS -- Some Display programs, utilities and Data files.
SDTS Home Page
USCG NAVIGATION CENTER