The video shows a basic user interface that lets the user configure webcam settings and application settings, take timed or instant pictures, and record video clips. Like many other parts of Windows 8 we've seen leaked so far, the application has a very basic design: a dark background, blue icons, white text, and an overall clean layout.
Under Application Settings, there are five options: Webcam, Audio source, Resolution, Frame rate, and Audio recording level. Webcam Settings also has five options: Brightness, Focus, Exposure, Zoom, and Flicker. Those are under the two tabs on top, while the three icons on the right let you do the actual picture taking and video recording. Once the content has been captured, you are given the option to view it and then either Accept or Retake it.
This application, if it ends up making it into the final release of Windows 8, is not yet complete. It looks as if the video preview function is currently not working. Furthermore, the application only works in full screen mode.
Windows should have received a webcam application a long time ago, but I think the reason it is getting one now is due to form factor. Laptops are outselling desktops and the tablet market is getting ready to explode. Most laptops and tablets nowadays come with front-facing cameras, so it makes sense to include software for the hardware.