If you have an Android phone and lost it somewhere you can easily find it using Android app called Plan B.

The app will automatically start running on your device and it will send its current location to your Gmail address over the next 10 minutes. If for some reason it doesn't start, you can borrow a friend's phone and text the word "locate" to your phone number

Android user can install this app after phone goes missing. Plan B is a free application. Unfortunately it may not always be a free option for Android user. It’s free because it's still experimental.

It's worth noting that GPS isn't implemented in the same way on all Android devices, it relies on your phone having access to a signal and it won't work if the phone is switched off. In tests, Plan B wasn't always accurate in some of its emails, but other emails (the ones with a higher accuracy rating), the location was more precise.

Plan B works in the U.S. only at present, ReadWriteWeb reports.