Here are some KML files for mapping some interesting live ham radio information.

APRS: current locations and tracks of APRS stations, APRS objects, and weather stations.  Visit http://aprs.fi and log in with your callsign (no password needed).  Configure the options if you like (probably want Fahrenheit degrees, for instance).  Click on the "Google Earth KML" link on the right hand column near the bottom, which will create a file "aprs.kml" and save it to your desktop.  Open that file in Google Earth.  Or you can download http://www.seattleacs.com/scripts/aprs.kml directly to your computer, preconfigured for Seattle.

IRLP: current status and location of IRLP nodes, also showing which links are connected. Download this file and open it in Google Earth: http://www.irlp.net/setup-irlp.kml

EchoLink system: current status and location of EchoLink enabled repeaters, simplex nodes, and computer nodes.  Download this file and open it in Google Earth: http://www.echolink.org/node_location.kmz