Though both Obama and McCain both play well in New Hampshire considering the political makeup of New Hampshire, I would have thought that Obama would either be leading McCain by anywhere between 2-5 points, not 11 points.
You have to remember that Republicans used to have a huge registration advantage in NH that has been steadily eroding over the past 15-20 years. Now in 2008, the parties have approximately equal registrations (about 31% each) while indepedents make up a huge 38%.
The key is that independents in NH are quite liberal/libertarian leaning. That means socially liberal and very anti-war. New Hampshire will be a pretty solidly blue state in the very near future.