Google 'Latitude' Location Tracking Coming to iPhone
Latitude is a new feature of Google Maps for mobile, as well as an iGoogle gadget, that allows you to share your location with your friends and to see their approximate locations, if they choose to share them with you. You can use your Google account to sign in and easily invite friends to Latitude from your existing list of contacts or by entering their email addresses. Google Talk is integrated with Latitude, so you and your friends can update your status messages and profile photos on the go and see what everyone is up to. You can also call, SMS, IM, or email each other within the app.
Google addresses privacy concerns in a FAQ and notes that the entire service is opt-in. While launching initially on BlackBerry, Windows Mobile, Android and Symbian S60, Google hopes to release an iPhone version soon.
This video shows how the service works:
Google is not the first to attempt this sort of service. Startup company Loopt provides a very similar service and was featured at WWDC as one of the first Apps for the iPhone [App Store Link].