This from the horse's mouth:

The five-member Norwegian Nobel Committee – four of whom spoke to The Associated Press, said awarding Obama the peace prize could be seen as an early vote of confidence intended to build global support for the policies of his young administration.

They lauded the change in global mood wrought by Obama's calls for peace and cooperation, and praised his pledges to reduce the world stock of nuclear arms, ease U.S. conflicts with Muslim nations and strengthen its role in combating climate change.

"Some people say – and I understand it – 'Isn't it premature? Too early?' Well, I'd say then that it could be too late to respond three years from now," Thorbjoern Jagland, chairman of the Norwegian Nobel Committee, told the AP. "It is now that we have the opportunity to respond – all of us."

Jagland said the committee whittled down a record pool of 205 nominations and had "several candidates until the last minute," but it became more obvious that "we couldn't get around these deep changes that are taking place" under Obama.