There are a number of programming languages and multimedia environments that support the TUIO
This is a list of example clients and libraries that can be used for developing multitouch applications:

Programming Languages:
C/C++ reacTIVision framework
Java reacTIVision framework
C# reacTIVision framework
Objective C
Python
Squeak (SmallTalk)
ActionScript (see the AS3 directory in the touchlib source)

Multimedia Environments:
Pure Data reacTIVision framework
Max/MSP reacTIVision framework
Quartz Composer reacTIVision framework
VVVV
SuperCollider
Flash reacTIVision framework