One application that caught my eye recently was Trak.

“Trak”, the site’s front-page reveals, “is an Android based Twitter client that can Tweet your geolocation, and read and display the geolocations of your Twitter friends. With street maps, satellite view and all.”

I’d have that in a minute. Here’s a screenshot of some Twitterers on the Trak map – I highlighted’em in red:

I can imagine applications like these being heavily, heavily used. I can’t wait to see how they perform in the real world!