According to this, several B-1 strategic long-range bombers are on their way to Guam, as well as at least one E-6 "Doomsday" plane, which provides command and control for U.S. nuclear forces should ground-based control become inoperative.
http://www.zerohedge.com/news/2013-04-05/us-secretly-deploys-b-1-strategic-bombers-e-6-doomsday-planes-near-north-korea