The upper part of the Main screen features a live map view of your current location. You can zoom the map image by using the two finger pinch move.
The center portion displays your street address as determined by reverse geocoding.
At the bottom are the three buttons that send your location data to your friends.
Select Email or SMS to send your message or select Copy/Paste to load the data into the iPhone's copy buffer. You can then paste the location data into any other iPhone app.