Sports-Illustrated contributor, Bare Naked Ladies Tour Photographer and PhotoShelter user, David Bergman was down in DC for the inauguration and set up a gigapan unit. From what I can tell, this $279 unit has some sort of robotics that allows it to carefully take a series of images which can then be stitched into one huge panoramic.
In other words, this:
Dave took 220 photos on a Canon G10 and stitched them together on his Macbook. See the whole thing.