Google Latitude makes a second coming to the App Store, this time it's real
Okay, for those of you who are not yet familiar with Google Latitude – it puts your friends on the map so you can see where they are at all times and not miss any opportunity to spend time together. It all runs in the background, so you don't need to keep the app open or even your phone unlocked. Security is also nicely handled and you can limit your location updates to city-level only, hide your location or turn off background updating altogether.
Unfortunately, minimum requirements are somewhat harsh and for the unlucky few running iOS prior to 4.0 - you will have to update to use the app, which is supported only on the iPhone 3GS and iPhone 4.