Here is an article discussing radionuclide evidence that has been collected at locations in South Korea, Okinawa, and Russia.
I will attempt to summarize it as follows: there is some convincing evidence that NK did succeed in detonating a very small nuclear device in the spring of 2010, as they announced.
The phrase "detonating a nuclear device" does not mean that they have a nuclear bomb. It means that they (probably) induced an explosive nuclear chain reaction to take place in an underground cavity.
The article is interesting, anyway.
As I posted to a Freeper above...the Norks have a very limited nuke capability, which may necessitate deployment with an ox cart, but be that as it may, anything the little fat ass psychopath can do, once he has committed to do it, he will do, even if it entails making some poor souls sneak across the border with it on their backs.
They are beginning to suffer the effects of the failing Chinese economy...in that what the Chinese once subsidized to them, they are demanding more substantial return.
Nork has nothing to offer.
Period.
They will reach desperation level in about three more months.
The country has already suffered greatly...there is some speculation as to whether they would fight or exchange their pitiful weapons for a potato.
Time will tell.