Well, Apple "stole" the television, and Microsoft stole the stereo... we're just going back in for the Betamax.

Seriously, using the source code for any project is a bad idea. There is not a chance in Redmond of Apple allowing you to do anything with it's source code. I suppose you could tinker with it on your own, and NOT distribute it. Otherwise, Apple will shut it down faster than you can say cease-and-desist.