You do realize that a (edit) by design small (/edit) nuclear weapon is only
*Snip*
This big. And that's a selectable yield of 10 or 20 tons (very close to the minimum practical size and yield for a fission warhead) up to 0.5 kilotons
http://en.wikipedia.org/wiki/Davy_Crockett_(nuclear_device)
Following 10+ years of development by some of the greatest minds in the field of nuclear physics. Somehow, I don't see North Korea matching the efforts of the US atomic program anytime soon.
Seriously, this whole thing is so much of a non-threat it's hilarious. The amount of people panicking here should be directly proportional to the number of members from Japan and South Korea, which I believe is approximately
dick.
If you live in the US or Europe, you're sooner going to die from 3 consecutive lightning strikes than a North Korean nuclear attack. Seriously, stop panic-mongering.