No Need Of expensive hardware just need webcam create multi touch

Simulate multi-"touch" input with M&Ms, tennis balls, or markers
Fun games, demos, community projects, and an extensible demo application
SDK with good documentation, add multi-"touch" to your own applications
Free and open-source project, games, and demos

http://touchless.codeplex.com/

Touchless needs you!

We have some great ideas to improve Touchless for users and developers alike. Together, we can create compelling, natural, and fun user experiences. Unfortunately, I have no regular contributors to the project, and a lot of my ideas and your feedback are falling to the wayside. Consider this your personal invitation to join the Touchless project as a contributor!

A Silverlight 5 beta will be available in the first half of next year, and the final release will ship in the second half of 2011.

enables developers to create premium media experiences and deliver rich applications across browsers, desktops and devices

Summary

We are really excited about the great new capabilities that Silverlight 5 will deliver, and look forward to getting your feedback. My keynote is available to watch online here if you want to see the new release in action and more information can be found on the Silverlight Website.