How to use find my iPhone
Although Apple’s cutting-edge new device tracking software Find My iPhone is now included by default with all iPhone 4s, iPads, and fourth generation iPod Touch devices, it can also be configured to run on older devices. Find My iPhone will run in the background on your iOS device and automatically track its whereabouts. If your device is lost, misplaced, or stolen, you simply have to log into your iCloud (formerly MobileMe) account and the location of your device will be displayed on a map. Here’s how to use find my iPhone on a Mac, PC or using the app on an iPhone, iPad or iPod touch. 
Find My iPhone can also send a message to your device to advise the finders that it is being tracked or just play a loud sound to help you determine under which couch cushion it has slipped this time. If worst comes to worst, you can use Find My iPhone to lock your device with a user-determined four-digit PIN code to render it completely useless to a thief. If your iPhone has fallen into the wrong hands, you can use Find My iPhone to completely and permanently erase all the data on the device to ensure that no sensitive files are seen by prying eyes.To start using this remarkable and useful software, use your device to sign up for an iCloud account. Go to the Settings menu in your device, and click on iCloud. Once the app loads, sign up for a new account by entering some basic information about yourself along with a user name and a unique password. If you already have an iCloud account, sign in, and then scroll down to the bottom of the Settings menu in your device. Press the Find My iPhone icon and make sure the service is turned on.
Next, go to Location Services, also in the Settings menu, and make sure the location-aware services on your phone are activated.
Find My iPhone can also send a message to your device to advise the finders that it is being tracked or just play a loud sound to help you determine under which couch cushion it has slipped this time. If worst comes to worst, you can use Find My iPhone to lock your device with a user-determined four-digit PIN code to render it completely useless to a thief. If your iPhone has fallen into the wrong hands, you can use Find My iPhone to completely and permanently erase all the data on the device to ensure that no sensitive files are seen by prying eyes.To start using this remarkable and useful software, use your device to sign up for an iCloud account. Go to the Settings menu in your device, and click on iCloud. Once the app loads, sign up for a new account by entering some basic information about yourself along with a user name and a unique password. If you already have an iCloud account, sign in, and then scroll down to the bottom of the Settings menu in your device. Press the Find My iPhone icon and make sure the service is turned on.Next, go to Location Services, also in the Settings menu, and make sure the location-aware services on your phone are activated.
If you should suddenly find your pockets empty and your iOS device missing, use an iPad, iPod touch or iPhone with the Find My iPhone app or find a computer and visit www.icloud.com. Type in your user name and password and the site will display a list of iOS devices that are registered in your name. Click on the one that you can’t find and the software will be activated. Find My iPhone will begin tracking your device’s location.
Once the location of your device has been determined, clicking on it should bring up a map with your device’s current location highlighted. A menu will also be available with a list of other actions you can take to help recover your device. These actions include Play Sound, Send Message, Remote Lock, and Remote Wipe. The Play Sound action will still play a loud noise on your iPhone even if the device has been manually set to Silent Mode. If your iPhone is anywhere in your approximate vicinity, use this option, and you will easily be able to locate your phone.
If the location of your iPhone is unfamiliar to you, it has probably been picked up by some opportunist. If this is the case, you should first lock it and then send a message to the finder to help encourage him or her to return your device.
This is a great and absolutely free service offered by Apple . I’d encourage everyone to take the time to set it up in the event that any of your valuable Apple products go missing.