Ok, here are some clarifications. And a disclaimer. I don't think Obama should have won. I like him, but he's not there yet obviously. But I understand why he did.
1. The Nobel Committee has long used the prize to sort of nudge the world in one way or another. Giving the prize to Carter was a not so thinly veiled kick to the shin for Bush to get off the Iraq warpath. He didn't get it. Same with the Al Gore and IGPCC prize, that was a kick to the shins for Bush again to stop neutering the EPA and join Kyoto. This is the same sort of thing. Obama's obviously not there yet, but he's trying and this is meant to make people think twice before pushing back against peace (ie: NK, Iran, Hamas, Avigdor Lieberman, etc.) Not like it'll actually work, though.
2. He should turn it down because he's not there yet. This will actually help his position because he'd look like less of an egotist. And in addition, he's been unable to close gitmo because he played his hand wrong and lost his bargaining chips with other nations.