In case you don't have latitude installed on your phone, the solution is simple: install Google Maps from the Google Play store or from the Android section of the website and automatically you'll have Latitude installed. Google Maps is just like any other application for Android: it's not bounded within the file system and you can install or uninstall it without affecting your OS. After you download Google Maps, it seems that when you start Maps or Latitude, you'll notice that it's the same thing. Latitude is partially integrated within Google Maps.
