Last I looked, North Korea had no roaming agreements and it was illegal to even bring your foreign mobile into the country.
http://www.gsmworld.com/roaming/gsminfo/roa_kpnt.shtml
I guess there goes my vacation in Pyongyang.
With respect to the prior post, Farmer's mobile by the way has no roaming agreement. Apparently it is a one way agreement with Ivory Coast.
http://www.gsmworld.com/roaming/gsminfo/roa_usfc.shtml