Kim Il-Ding-Dong says they detonated a nuclear device. There seems to have bene some seismic activity detected, whether from an acutal nulcear device or Kim eating bad kimchee has yet to be determined.
Political seismic activity, on the other hand, has been measurable. South Koreans burning Kim in effigy to Japan pulling its long dis-used saber out just a bit and finally President Bush coming down hard against the piratical regime in Pyongyang.
If this is true, so much for giving Kim all that oil and help with a peaceful nuclear reactor to buy him off from building the blasted things.