Together with Jonas Jongejan and Ziv Hendel from PrimeSense http://www.roxlu.com/ created a working version of OpenNI and the complete driver (SensorKinect) for Mac OS X! Ziv is working on a Mac binary for NITE! As I'm working towards a build of OpenNI for openFrameworks, which works on Linux and Windows as well, I went through the code so I got a good understanding of the internals of OpenNI. Basically OpenNI works like this: you create an object in your code which is called the context. This context object contains all necessary information which is necessary for the framework. If it's not clear what OpenNI is, let me give you a short introduction. OpenNI isn't much more than a couple of coding "rules" for systems which work with natural human interaction. The framework makes use of "modules". When you create a context object in your code the modules will be loaded into the context/framework. When the modules have been loaded and initialized you can use them in your application.