This page provides details of applications implementing the GeoSMS standard.
It can be downloaded through the Android Market (search for “i am here”), and is also available as an APK file IAmHere.apk.
To install the APK file on your phone without going through the Android Market, first install a file browser such as Astro. Next, under Settings -> Applications check the option Unknown sources. Then copy the APK file to the phone’s SD card and select it with the file browser. Follow the prompts to install the application.