On my website I have published instructions and scripts that explain how you can link a GPS tracker to Homeseer devices.
It uses a combination of: GPS-Trace tracking functionality, Jon00's email plugin and my Geo-fence script. Not the easiest but it really helps me and I already had the Jon00 plugin and the gps-trace integration anyway.
http://www.domoticaworld.com
See the blog items or click on the "scripts" menu and "GPS Geo Fence"
Cheers
DJ