"As of February 2005 Defense Intelligence Agency analysts were reported to believe that North Korea may already have produced as many as 12 to 15 nuclear weapons. This would imply that by the end of 2004 North Korea had produced somewhere between four and eight uranium bombs
. The DIA's estimate was at the high end of an intelligence community-wide assessment of North Korea's nuclear arsenal completed in early 2005. The CIA lowballed the estimate at two to three bombs, which would suggest an assessment that the DPRK either had not reprocessed a significant amount of plutonium from the 8,000 spent fuel rods removed from storage in early 2003, or had not fabricated a significant number of weapons from whatever amount of plutonium had been reprocessed. The Department of Energy's analysis put North Korea's stockpile somewhere in between, which would be consistent with the roughly 7 or 8 plutonium bombs that could be produced from all existing plutonium stocks, with no uranium bombs.
If one assumes that the DPRK produced sufficient plutonium for eight bombs, and expended one of these bombs in a test in Pakistan in 1998, then as of 2005 their plutonium bomb inventory would be seven weapons. Taking the mid-point of the DIA's estimate of between four and eight uranium bombs, the plausible uranium bomb stockpile as of early 2005 would be six weapons, increasing at a rate of one bomb every two months. Thus the early 2005 stockpile would be 13 weapons, growing to about 20 weapons by the end of the year."
http://www.globalsecurity.org/wmd/world/dprk/nuke.htm
They also are said to have missiles with a range of up to 9,000 km.
"The Taep’o-dong 2’s major use is as a weapon of international blackmail. Easily equipped with a nuclear weapon, it is the first direct threat to the United States from North Korea. It will likely be used as a threat of nuclear escalation in response to any American intervention during a second Korean war. Just as the People’s Republic of China (PRC) Lt. Gen. Xiong Guang Kai stated that Americans “care more about Los Angeles than they do Tai Pei,” North Korea will likely rely on American unwillingness to lose cities rather than withdraw from Korea. In addition, it will likely be used to blackmail wealthier countries for energy and food, similar to how the North Korean nuclear program has been used. It is also a major income generator as an item for export."
http://www.globalsecurity.org/wmd/world/dprk/nuke.htm