The official Kinect for Windows SDK has been officially released today.
Alongside with the SDK, a new sensor is available. The newly released hardware is optimized for use with computers and devices running Windows 7, Windows 8 developer preview (desktop applications only), and Windows Embedded-based devices. If you want to buy it, you can go there: http://www.microsoft.com/en-us/kinectforwindows/purchase/
New features (for a Kinect for Windows sensor, not the Xbox 360 one!):
Commercial license. Now, using a Kinect for Windows sensor and the official SDK, you can develop commercial applications powered by Kinect technologies.
Enhanced sensor capabilities. The new sensor offers a Near Mode field of view, which enables the depth camera to see objects as close as 40 centimeters in front of the sensor. In addition, it is possible to plug up to 4 Kinect sensors into the same computer.
SDK improvements. The Windows SDK offers an improved skeletal tracking, which enables developers to control which user is being tracked by the sensor, and the latest Microsoft Speech components with improved speech recognition accuracy. In addition, API consistency and ease of development have been enhanced.
Raw sensors streams. Added support for both Default and Near modes and also give more information about depth values outside the range than was previously available. There is also improved synchronization between color and depth, mapping depth to color, and a full frame API.
New features can be used only with the new Kinect for Windows sensor, but it is still possible to develop with the Xbox 360 sensor. Anyway, it is advisable, in case you are developing a commercial product, to switch to the new hardware as soon as possible.