Imagine an organization which sells drugs, kidnaps people, sells nuclear weapons to anyone who will buy them, that can turn on officers within the organization who chose the wrong side in a power struggle and kills their entire families, brainwashes people, and steals humanitarian aid meant for starving people. Now just imagine this organization was masquerading as a government just north of the DMZ. This organization survives because most of its people are brainwashed and don't know the truth (with the exception of people living near the Chinese border).
What would happen to the organization and the entire system they created if people started giving their citizens information about the outside world.
There are actually groups doing this right now. The one I know about is http://www.opendoors.org/
there work can be explained in this article http://www.opendoors.org.za/eng/persecuted_christians/news_persecuted_church/news2011/03_march_2011/nr_1_on_2011_wwl/
I know there are others working to bring information into the hands of the oppressed starving people up North, I just don't know their names; So please share with me. Imagine people working together from many different faiths, political views, and ethnic backgrounds to bring change to North Korea. I believe it would be unstoppable.
For more information on North Korea there is the daily NK newspaper written by North Korean refugees in South Korea. http://www.dailynk.com/english/index.php