Windows Flip and Flip 3D
This feature is included in the following editions of Windows Vista:
Windows Flip and Windows Flip 3D render live thumbnail images of the exact contents of your open windows, making it easier to identify the one you want. Windows Flip allows you to flip between windows, while Windows Flip 3D dynamically displays all open windows in a three-dimensional view.
Windows Flip 3D
Windows Flip 3D uses the dimension of visual depth to give you a more comprehensive view of your open windows.
Windows Flip 3D also allows you to render images of live processes such as currently playing video. Use the START+TAB keys to initiate the 3-D view, then flip through open windows by using arrow keys or the scroll wheel on your mouse to quickly identify and select the one you want.

Scan all open windows in one easy view.
Windows Flip
By repeatedly pressing ALT+TAB, you can scroll through a visual list of your open files and programs. Using Windows Aero technology, Windows Flip renders live thumbnails of the exact contents of those open windows.
In Windows Aero, live taskbar thumbnail images display the actual contents of both windows that are currently open and those that are minimized in the taskbar. When you rest your mouse pointer on a tile on the taskbar, you'll see the "live" contents of that window without having to bring it to the foreground.

View open windows as live thumbnail images.