If you like to keep tabs on your geocaching statistics, you'll love CacheStats.
ClayJar GPX Watcher
Watcher is a GPX utility available at no charge which helps you manage your pocket queries.
EasyGPS is the fast and easy way to transfer waypoints, routes, and tracks between your computer and your Garmin, Magellan, or Lowrance GPS.
GPSBabel converts waypoints, tracks, and routes between popular GPS receivers and mapping programs. It also has powerful manipulation tools for such data.
A powerful utility to convert your GPX files into other formats, in particular, this tool is useful for creating HTML data suitable for sending to a handheld device using Plucker or iSilo.
GSAK is the all in one Geocaching and waypoint management tool. Major features include: Multiple databases, sending/receiving waypoints to GPSr, Google maps, conversion to many mapping formats, PDA output (including CacheMate support), HTML output, extensive searching, macro support, backup and restore, distance/direction from other waypoints (including caches, locations, post codes) and much more.