Plug Spy

Plug-Spy is an instant warning system for your MacBook in case that someone try to take it away or is entering a wrong password in the standard OS X login panel. It's easy to setup and integrates seamlessly with Mac OS X and Apple iCloud "Find my Mac".

There is no additional password or shortcut you have to remember. Plug Spy auto activates when your screen is locked and start an annoying high volume alert sound and send a Growl notification when your MacBook gets unplugged from the MagSafe power adapter.

With access protection enabled, you will also get notified when someone enter a wrong password in the login panel, try to access your MacBook with a different user account, or restart your Mac in Safari Guest mode.

With Boxcar or Prowl on your iPhone you can receive the notification right in your phone to initiate further steps.