Surface 2.0 SDK. Multi-touch in WPF 4 Part 3 – Manipulation Events - Anson Tsao's Blog. One of the most common usage of multi-touch input is for panning, zooming and rotation.
With WPF4, the easiest way to implement these gestures is by using the Manipulation events on UIElements. Manipulation events also support simple inertial physics for a more fluid user experience. Download Details - Microsoft Download Center - Microsoft Surface sample for Microsoft Silverlight.