Forget that last comment about GeoBuddy for geocaching.
EasyGPS and GeoBuddy will not read GPS location data from a GPS receiver and do navigation on a map. They are what I think of as "administrative" programs. They will load data (geocaches, waypoints, routes, tracks) from a supported GPS into their database on the PC. Then you can do stuff like geocode pictures (EasyGPS) and manage geocache information (GeoBuddy).
With GeoBuddy you can bulk load geocaches into the supported GPS.
The key to all this is that the receiver must either be a standalone personal navigation device, like Garmin Nuvi or eTrex or Colorado, etc. Or they must have data logging capabilities (for EasyGPS to get the track data for geocoding pictures).
At least that's what I've figured out so far from looking through the documentation online.
For whatever it's worth, it doesn't work very well, either. I tried getting EasyGPS to load the geocaches, waypoints, tracks and routes from my eTrex Legend HCx. It tells me there is no GPS connected to the USB port. When I acknowledge that error message it tells me there is none of that data on my GPS.
Truth is that it was connected to the GPS port and it has geocaches, tracks, waypoints and routes stored on it.
I was not impressed so far.
...ken...