Nothing so far, and it's pretty likely nothing will come of it. North Korea has played up like this before.
It should be noted, the invasion of NK would probably be the right thing to do - I've a feeling the majority of those anti-war types haven't read up on the atrocities NK doles out on its people on a daily basis - concentration camps, rapes, murders, mass starvation... I could go on. If a person transgresses, no matter how minor it may be, his/her entire family is sent to the camps, and killed off either by simple rape and shooting, or being overworked in the mines. I could go on all day.
North Korea is pretty much a modern-day holocaust - but nowhere near as concentrated (it's generally systematic abuse across the entire country) and not as obvious due to the juche isolationist idealogy NK has. I think it's pretty amazing and shocking how it is so little known that NK is in a nutshell one of the most depraved and ****ed up countries in the world. It isn't just a 'we're doing economically poor and people are starving' situation. Kim Jong Il isn't just some crackpot figurehead for Americans to make silly movies of. As far as evil despots go, he's the crème de la crème.