1. Always show respect to the Koreans leaders and avoid offending the local guides and people. At certain places especially statues of the leaders we will often bow to show our respect according to the local customs.2. We are not allowed to use the local currency in North Korea.3. Professional video cameras are not allowed to be taken into the DPRK, but handheld digicams have recently been allowed as long as you don’t film anything you’re told not to! Regular digital still cameras are fine, for professional cameras, lenses less than 250mm are allowed- anything over that could be retained at customs until you depart.4. E-books are fine, and normal books are OK as long as it’s not a Bible, Qur’an or any other religious text. A couple of people were in trouble because they were bringing Bibles with them, so e-hem, no religious text book.
Source: How to enter North Korea