OS X Mavericks: About Find My Mac
If you misplace your Mac, iCloud Find My Mac helps you locate it. Before your Mac goes missing, make sure it has Find My Mac turned on in iCloud preferences and Location Services turned on in the Privacy pane of Security & Privacy preferences.
When you need help finding your Mac, go to icloud.com/#find on another computer or use the Find My iPhone app on your iOS device. As long as your lost Mac is connected to a Wi-Fi network and not asleep, you can locate it on a map. You can play a sound on it, lock it, or erase it completely if it’s connected to the Internet via Wi-Fi or Ethernet.
For information about using Find My iPhone, open the app on your device, then tap Setup Instructions. For information about using Find My iPhone from another computer’s web browser, see: