Login HD will be your most used, trusted, reliable and elegant app you have on your Mac the moment you install this gem.
It is very simple. Login HD is the locking device we have all been waiting for.

Login HD was designed and built to address every possible desire a user could ever have when it comes to locking and controlling a locked screen. Hiding this massive effort behind a simple user interface, that is super easy to use was the biggest challenge.

Link for more information: http://itunes.apple.com/us/app/login-hd/id488641047?mt=12