GPX, or GPS eXchange Format is an XML schema designed for transferring GPS data.
GPX plugin allows you to display GPX files in wordpress. In otherwords if you can save the contents of your GPS as a GPX file, you can display it in wordpress using microsoft virtual earth as the display engine. 

Notes
This Plugin is still alpha quality, and is currently just for debugging feedback purposes.
It’s only been tested using wordpress 2.03, so i’ve no idea if it works with earlier versions.

Useful GPX utilities
Microsoft produce a nice little app specifically designed to download tracklogs from garmin gps units, which is handy. You can get wwmx trackdownload here.

Version History
0.1 - first attempt - required hacking of template files
0.2 - should work as a plugin now -just a debug version - quite buggy
0.3 - bug fix for 0.2
0.4 - See gpx_plugin posts for details
0.5 - See gpx_plugin posts for details
0.6 - Bug fix for 0.4 :)
0.7 - See gpx_plugins posts for details

To do
Move over to proper XML in AJAX bits
Look at 3D route flythroughs.
Look at GeoRSS?
 

Docs
readme0.7

Download
zip0.7