Q: I have the Find My iPhone App on my iPhone and can use it from my iPhone, but I would like to know how to use it from my computer. It doesn’t do me any good to use it if I know where my iPhone already is.
– Darlene

A: Although there is no standalone “Find my iPhone” application for the Mac or PC, you can easily access this service simply by logging into your iCloud account at http://www.icloud.com from just about any modern web browser.

Once logged in, simply select the “Find My iPhone” icon.
You may be asked to supply your password again for additional security and privacy after which you will be taken to a map view. The Devices button in the top-right corner will drop down a list of all of the iOS devices and Macs associated with the current iCloud account, and the location status of each.
Clicking on any of your devices will centre the map on that particular device, with controls for zooming in and out and options to play a sound to help you locate the device, remotely erase the device, or lock the device in iOS 5 and earlier or enable “Lost Mode” if the device is running iOS 6. The latter option locks the iPhone and allows you to enter a phone number and message that will be displayed on the screen to assist an honest finder in getting your iPhone back to you.
“Lost Mode” also begins tracking the movement of your device so that you can see where it’s been while it’s lost, rather than merely reporting its current location.
If the selected device is offline (e.g. out of network coverage or turned off), then instead of a map you will be shown a screen with the same options along with a checkbox to send you a notification once your device comes back online. Any other options you choose here—Play Sound, Lost Mode, Erase—will also be performed as soon as your device comes back online.