The iPhone is a smartphone manufactured by Apple that allows users to download third-party applications through the "App Store." Applications in the App Store cover a variety of needs, including location-aware apps that let individuals share their geological location at specific intervals or in real time. Individuals sharing their locations are provided with privacy features so that they may choose when to broadcast their location to the respective apps for other users to see.
Touch the "App Store" icon on your iPhone. Touch the "Search" icon at the bottom of the screen. Search for "Loopt" if you are using an iPhone 3G and either "Loopt" or "Google Latitude" if you are using an iPhone 3GS or iPhone 4. Download the application you choose on your iPhone and on the iPhone you wish to track.
Touch the "Loopt" icon. Sign up for a new account using the "New User" button and input your personal details. Once finished, add new friends to track via Facebook or Twitter. If the person you want to track does not have either, you can use the email address or phone number he used to sign up with Loopt to track his location. Use the "Map" feature to see the person you are tracking on a map and use the "Friends" feature to "Ping" an individual in your friends list whose location you want to know. Loopt only shares location information after a person checks in using the app or accepts your Ping request.
Touch the "Google Latitude" icon on your iPhone. Create a new account and a way for friends to find you. If the person you wish to track is using Google Latitude, add her by touching the add friend icon (the silhouette of man with a plus sign) either on the Map or friends list. Enter your friend's credentials to begin receiving her location information and tracking her in real time. Since the iPhone 3GS and iPhone 4 allow for multitasking, Google Latitude can track individuals even when the app is not open. To do so, access the "Settings" menu, represented by the nuts and bolts icons, and instruct the person you wish to follow to choose the "Detect Your Location" option under "Location Reporting" and to turn on "Background Updating" in "Options."
The person you wish to track doesn't necessarily need to have an iPhone. If he has an Android-enabled device or a BlackBerry, he can download the respective apps on his phone and still allow you to track him. Although you can track a person in real time using these apps, the GPS radio constantly running while supplying data will put a tremendous strain on battery life and should be used sparingly.
You should not install either of these tracking applications to a friend's phone without her consent or knowledge.