Ryan Smith over at anandtech.com gives a great overview of Microsoft's pre-beta of the Windows 8 tablet interface from Anaheim, California at Microsoft’s BUILD conference.

Microsoft’s tagline for BUILD is that “Windows 8 changes everything”, and you will be using Windows 8 significantly differently from Windows 7. The big thing with Windows 8 is Metro. It's a very touch-friendly interface to Windows, not replacing the Windows desktop you know, but complimenting it. Metro includes many of the features found in other tablet OS's including an app store and lots of swipe interfaces.