Use Find My iPhone to Locate Lost or Stolen iPhone

Find My iPhone is an awesome iPhone feature that allows you to locate your iPhone on a map and remotely lock or erase it.

But how to use it?

Set up Find My iPhone through iCloud: Go to settings > iCloud, then turn on Find My iPhone.

Set up Find My iPhone through MobileMe:
1. Go to settings > Mails, Contacts, Calendars > Add Account
2. Tap MobileMe
3. Enter your Apple ID and password, then tap Next
4. Turn on Find My iPhone

see the detailed steps at http://goo.gl/73uGEh