GPS2CAD is a powerful program that allows you to connect to a portable GPS device, download the waypoints, routes, and trackpoints, and do some amazing things with them:
Convert them to the datum of your choice and plot them in AutoCAD
Automatically view them on Aerial Photos, Topo maps, or Tiger maps (census maps) all retrieved from TerraServer-USA, one of the largest repositories of public domain mapping on the net
Export them to a variety of formats for use in other programs
