North Korea is the closest you can get to visiting another planet. I toured in May 2010 (see parts 1, 2, 3, 4 and photo album) and also discussed two of the principal tour agents, Koryo Tours and Asia Live. Koryo Tours is the major player. I went with Asia Live for a private tour and had an excellent experience. All operate within narrow restrictions and in partnership with the DRPK’s Korea International Travel Company (KITC) which generally does not deal directly with tourists.
Uri Tours is new to me, I am not familiar with their track record, yet am intrigued by several of their Signature Series tours, tempting me for a second visit. The standout is the 13-day DPRK Mountain Tour, with charter flights and access to destinations I have not seen on other itineraries. The DPRK is no bargain destination, and this tour is top-end because of scope and length, US$3,995 single/$3,595 double, which, like other operators, only includes cost starting from Beijing. Those who know my twitter aversion will realize how much I wanted to win their giveaway by seeing my constantly refreshing my feed.
The biggest planning principle to understand is that it is extremely difficult to make even minor changes to any itinerary once it is approved by the DPRK authorities and you are in-country, even on private tours.
Being effectively incommunicado with the outside world for a prolonged period is another stumbling block for many would-be visitors.
Uri Tours brings more options to the table, again I cannot at this point vouch for their tours, though DPRK is not the kind of destination that lends itself to fly-by-night scam tours. Each of Koryo Tours, Asia Live, and Uri Tours offers different programs. For such a major, costly undertaking I strongly recommend carefully considering all options.