Google announced the Android Device Manager. The app provides a feature for finding a lost Android-based phone.
Android Device Manager lets you quickly ring your phone at maximum volume so you can find it, even if it’s been silenced. And in the event that your phone or tablet is out of earshot (say, at that restaurant you left it at last night), you can locate it on a map in real time.
The app requires 2.2 or above and is expected to eventually be available to other devices besides the phone.
Both Apple iPhones and Microsoft phones have similar services.