There are 3 ways to write Multi-Touch applications in Windows:
1. Using PQ Labs Multi-Touch SDK & Gesture Library
Download PQ SDK: C/C++, WPF(C#), C#(DllImport), Flash/Flex/AIR AS3, Flash AS2, Java
2. Using Windows 7 Native Touch
Support: C/C++, C#(WPF 4.0), Flash (Flash Player v10.1 or above), AIR 2.0
OS Limitation: Windows 7 Home Basic or Starter Edition does not support Multi-Touch.
3. Using TUIO
Support: C/C++, Flash (AS3), Java, C#/WPF

There are 2 ways to write Multi-Touch applications in Mac OS X:
1. Using PQ Labs Multi-Touch SDK & Gesture Library
Download: C/C++/Objective-C, Flash/Flex/AIR, Java
2. Using TUIO
Support: C/C++, Flash (AS3), Java










