It depends. If MS is offering a complete SDK, then it's a whole nother ball of wax... unless you're on a Mac or linux distro. IANAL, but I also assume there will be legal issues with distributing a commercial kinect app without the express approval of Redmond.
the one we released (adafruit) with hector is open source, commercial use allowed.
to use microsoft's you'll need to wait until they allow commercial use (from what is reported that's later in the year, maybe even 2012).
Why legal issues? If MS was thinking ahead, they'd freely let people sell apps using the sensor. It sells more Kinects. You could pretty much bootstrap a whole app ecosystem based just on the Kinect (on Windows only thankyouverymuch)