Microsoft have confirmed that the rumoured official SDK for the PC version of their
all-seeing demon-camera of judgement motion tracking depth camera thing will have a PC SDK soon. Here's the statement. Here's the gist of it: "While Microsoft plans to release a commercial version at a later date, this SDK will be a starter kit to make it simpler for the academic research and enthusiast communities to create rich natural user interfaces using Kinect technology. The SDK will give users access to deep Kinect system information such as audio, system application-programming interfaces, and direct control of the Kinect sensor."
So nothing commercial for now, at least, but we can expect some unexpectedness once this gets into the hands of the inventor-men.