Gearth-1
Here’s an idea that I can’t hack this week since I’m on the road…but have at it: each person who wants to publish their location can via the status of Skype/AIM/Jabber/MSN/etc. A buddy “bot” on that system reads the info and makes a KML file (Google Earth). Then you just drag all the KML files of the people who you’re looking for in to Google Earth. See our how-to on doing this with photos. GeoBloggers does this now with photos and other items (Meetro does this too) – Link.