GPS Twit - Geo-Caching was one of the main mobile buzzwords of 2008 and GPS Twit takes full advantage of this fact. The application works on Windows Mobile phones that come enabled with GPS. The program pulls your GPS coordinates and posts them in front of your tweet. This is a great application if you want to say "At The Club...Come Meet Up" or something along those lines. If you can't hear your phone where you are your friends can still find you, throw the coordinate in Google Maps or another GPS program and then they're on the way to your location. I like apps that do all the work for me as I go about my regular everyday business and that's exactly what GPS Twit does.
This app, for the iPhone and Windows Mobile, makes it easy for your friends to find you. GPS Twit answers the question, “Where are you and what are you doing?” by polling your GPS and posting it to the front of your tweets.
Here's a Screenshot, notice the nice clean and simplistic interface:

click to enlarge