This is a plug-in for several PIMs that allow you to view the location of a contact within Google Earth. Download Squad
Via Download Squad
I saw a press release on GeoTorrent on the Geoplace website and checked out the GeoTorrent.org site. It is based on bitTorrent technology. They seem to have mostly satellite mosaics right now, and also some TIGER data.
Here is a link to the GeoTorrent website if you want to check it out: