kakiloc.com
KakilocIs a Location-Based Social Networking Service. Discover where your friends are and what they do. Follow them on Google Maps. Send messages to them by SMS or Email. Be notified when they physically reach a specific place. Create reminder for yourself when you are near a specific area. And even Find new friends that are visiting the same spots as you. Kakiloc is officially defunct; this notice was sent out on 11/30/2007:.
http://www.kakiloc.com/