At risk of repeating other respondents, you can just go. You can find a tour organiser and simply book onto one of their tours, or you can organise your own through the DPRK state tourism companies. Going with an established tour organiser is by far the easier way to do it. I went with Koryo Tours in 2012 and it couldn't have been easier; filled in the form, emailed my details, paid a deposit and the rest at the start of the tour.
But to reiterate, you can just book on a tour. There's no problem or difficulty doing it.
Also, the government occasionally allows a radio amateur to operate. Just this month, North Korea was active on HF (last time was 2002). They'll be active again in Feb 2016:
But to reiterate, you can just book on a tour. There's no problem or difficulty doing it.