The company the OP used (Koryo Tours) is the easiest way to get in if you're American, though they're limited to when NK will let Americans arrive (a few weeks each in 95, 02 and 05, which is when I went).
If you're American and you want to go, go on the *first* tour after they open up the border again. Subsequent tours, at least in 05, were filled with unreformed communists and media types, whereas our tour was generally just interested travelers who played games like "don't bow to the statue", "yell things in your hotel room to find the bugs" and "sing the star spangled banner on the bus karaoke machine".
It's too bad, but it's very difficult for tourists to see "real" North Korea; aside from Kaesong, Pyongyang, mountains in the north and a few coastal cities, you're not really allowed anywhere, so it's tough to get a read on what NK is actually like. I'm actually quite interested in traveled up to Dandong and the Korean AR in China, where a lot of Korean entrepreneurs scurry across the border to.
Hopeful sign: a few backwards ballcaps that I saw on Koreans; they gave me a thumbs up after I yelled out to them. Word that up, Kim. Also, despite the politics, I only got one hostile reaction from the dozen or so Koreans I told I was American (in some combination of Russian, English and Chinese, which seem to be the most standard foreign languages in DPRK).
Thanks for the post!