trips to the North

I am fairly sure it is not possible from Seoul. Years ago some Korean travel agencies arranged tours to scenic spots in North Korea, for Korean tourists only, but they did not go to Pyongyang. The easiest place to get to North Korea from is Beijing, where there are plenty of agencies who arrange tours. Koryo Tours comes highly recommended, though there are others which are less expensive. A search of this forum should yield some names.

The cheapest place to get to North Korea is to arrange your trip in Dandong, China which is on the Yalu River across from North Korea.

Although written several years ago, I don't think things have changed so you might find this link helpful: North Korea Travel

Other sites about North Korea travel:
Travel in North Korea

Visiting, Working or Investing in North Korea

North Korea Travel and Tourism

Koryo Tours

But the threads you really want to read are these: Going to North Korea from Dandong and Cheaper travel agency for North Korea.

Ruth

Its not possible to visit Pyongyang from South Korea, not at all. You must go through China, I'm sure its at least possible to go from Russia but I've never heard a tourist doing it.

Patrickb - there is a report on this forum of a traveler visiting North Korea by train from Russia. I think the TT user's name is Utti and he is a big fan of long distance train rides.

Ruth