Yeah, the nominations had to be in by February 1st, so you cannot seriously argue that Obama had done anything for world peace by then. He hadn't even arranged his underwear drawer in the White House yet.
Of course I would argue that he still hasn't done anything for world peace but that has nothing to do with this Nobel Peace prize. The fact that it has gone to complete scum like Kissinger, Gore, and Arafat (among others unworthy) shows it's a bullshit award anyway.
Edit: It's also overtly hypocritical to award a Peace Prize to the "Commander in Chief" of the biggest global military spread since the height of British Imperialism.