Probably offtopic, but highly recommended: USAPhotoMaps
http://jdmcox.com/
The program is free, but it encourages users to make a voluntary donation,
to the point of being nagware. The nag is displayed when you exit the
program. I like it, I use it, but it doesn't qualify as pure freeware.
Consider it an option only if no genuine freeware offerings meet your
needs.
This page lists software that works with Garmin GPS units. You'll probably
find similar lists for other units, if you poke around the site a bit.
http://www.gpsrunner.net/html/software.html
Several others are listed as freeware, but I haven't tried any other than
USAPhotoMaps, so I can't vouch for their status a pure freeware, either.