It is not possible to use Kinect on PC as of yet because of the obvious problem with drivers. Microsoft made it clear they do not plan releasing PC drivers for Kinect. Moreover, Microsoft made it very clear they do not like the idea of someone making PC drivers for Kinect.
Status of open-source Kinect driverThe Open Kinect projectAlternative is to port our software to Xbox. Again, we talked to Microsoft and they do not like this idea. We cannot port software to Xbox without official Xbox SDK and Microsoft's permission. Xbox is a closed platform.
By the way, putting together multiple Kinects will never ever work, because Kinect uses structured light approach for reading scene depth:
Video explaining how Kinect reads scene depthMultiple Kinects in one room will interfere and will not work at all.
To sum it up, motion capture with Kinect is not possible yet.
If we resolve the problem with drivers, Kinect will make a nice entry-level animation solution. Due to obvious problem with occlusion in any single-camera system, Kinect will be no better then a 2-camera setup of current version of iPi software, but with smaller capture volume.