Describe ApRs here.
[http://aprs.rutgers.edu/APRS used with packet radio by Hams and allows real time geographical plotting]. It's used for plotting the position of vehicles, the status of weather, radio direction finding and much much more. It envolves mapping, GPS tracking, packet radio, etc. It is a VERY interesting facit of packet radio and has much to offer most everyone including non-hams that just want to watch over the internet.
Where is Doug Ferrel right now? [http://map.findu.com/kd4moj Here's a real-time map]. [http://www.tallahassee-scanner.com Scanning Tallahassee] has more.
[http://www.pocketaprs.com Here's a PocketPC] with real-time tracking maps! Yips! [http://wes.johnston.net/aprs/ APRS] looks alot like what [http://www.graviton.com Graviton] which uses cellular to relay moving telemetry.
I don't know anything about APRS but the implications seem significant for wireless networks. Imagine runners with a PocketPC being tracked with real-time telemetry on heart beats and respiration. I smell a $500 Nike shoe/watch!