My initial reaction to Barack Obama's Nobel Prize was probably a lot like yours: "Uh, isn't this a little premature?" And I do think on some level, it was bestowed because the Nobel committee wasn't allowed to give out a negative award to the Bush administration for achieving the precise opposite of what this award was intended to honor.
But as I read all the different op-eds and viewpoints, I'm drifting to the view of folks like Joan Walsh and Juan Cole who think it makes sense. I also don't think it's a huge deal if the Nobel Prize is given to the undeserving. The world didn't end when Kissinger got one and that was like giving a humanitarian award to Hannibal Lector. The Nobel Prize is just the opinion of a bunch of people whose names we don't know and whose actions we don't care about the other 364 days of the year.