The early builds of Windows 8 intended for internal testing are out in the wild. Guys who had their hands with Windows 8 are revealing exciting features of the new operating system. Few weeks ago we saw screenshots of logon screen with Metro UI design and then a walkthrough video of logon process and customization.
Here is another video that shows logging in to Windows 8 on touch based devices & tablets. The user interface to unlock/logon is based on pattern matching that is quite similar to Android unlock screen interface. Check out this embedded video