Actually, it was from Minot AFB ND, to Barksdale AFB, Louisiana, in August of 2007.
At the time, some speculation tied this to all the tough talk about attacking Iran, that there might have been a black budget funded special ops group moving nukes into position to either be used as a justification, or ready for some staged event to justify their use against Iran.
But this was like a year ago.
http://www.washingtonpost.com/wp-dyn/content/article/2007/09/05/AR2007090500762.html