GPS

Check out Bruno's stuff, since he's much more into it than I am.

Mac OS X:

• GPS Connect, which can download waypoint data from Garmin devices via an USB-to-serial converter.

Windows:

• G7ToWin - simple waypoint, track and route import/export for Garmin devices.

Generic UNIX/Linux:

• GPSDrive and Roadster, Gnome applications
• gpsd, a TCP daemon to echo GPS data in a more palatable format.

Series 60:

• A simple Python-based GPS interface

Multiplatform:

• GPS Babel - cross-platform data importer/exporter/converter.

• Tom Tom Go - the only really good GPS device I've handled so far, and which has been recently enhanced.