North Korea has been cloaked in secrecy for decades, off limits to the rest of the world and obscuring the rest of the world to its citizens. North Korea placed very narrow restrictions on travel and forbid much of the world from joining. Only recently have family of North Korean citizens been allowed into the country for short visits.
North Korea is also opening up slightly to newspapers and TV stations. Recent highly controlled, limited access to the country by the international media has begun to lift the shroud from North Korea, but the country is still one of the most reclusive nations in the developed world.
Traveling to North Korea has been impossible for years for the average traveler, but as the country opens up slowly, the opportunity for travel is beginning to present itself. Travelers have to book tours through a North Korean travel agent and the Korean Friendship Association, and anyone suspected of being a journalist may be denied entry.
American travelers are almost never allowed into the country except as part of special delegations invited by the government.
If you go
Under no circumstances should you say or joke about anything that could be perceived as a threat or criticism of Kim Jong-Il or the country itself. This is extremely important. You'll be in real trouble, although your travel guide will probably take the more extreme punishment as you are somewhat protected by your foreign citizenship.