This would be a dangerous game. If the DPRK really has nukes - who tells us that they use it in the way we are thinking of? It is probably much easier to smuggle a nuclear warhead into a big city in America and detonate it there than shooting it with a ICBM. Kim Jong Il is probably working on 3-4 warheads at the same time. If the USAF would bomb their nuclear facilitys, they could respond with a nuclear terror strike. We wouldn't even know who the terrorist was (Osama?, Kim Jong Il?, al-Sarkawi?, Chirac? (huhu) etc. etc. etc). Not very funny. It is probably better and more effective to eliminate the "dear" leader through a good sniper or some poison in his coffee. If he and his offspring are wiped out, freedom will find a way.
BTW - those links about north Korea are much funnier than their dammed nukes:
http://www.kdvr.de (Sorry - in German but exremly dumb)
http://www.korea-dpr.com/ (The long loading times are a real eperience - must be a top-of-the-line server of their own production)