It turns out that yesterday's report was true, as today Microsoft released the beta version of its Kinect for Windows software development kit. While certainly not the first development software released for Kinect, the beta SDK does mark the first kit officially offered by Microsoft. The kit is available in both 32-bit and 64-bit flavors, requires Windows 7 and is for non-commercial use only.
The Kinect for Windows SDK can be downloaded directly from Microsoft here. Now get to work on those Kinect hacks ... er, applications.