Discussed at Marginal Revolution and Freakonomics.
The study finds that liberals and conservatives don't seem to score different when tested for "closed-mindedness". What I'd like to know is if this could be tested by profession. Personally, I feel lucky that I'm at a place like Susquehanna University where most people are accepting of political differences. That being said, it was explained to me once that the opposition to the president's policies on spending by the tea party was largely just fueled by racism. I have also heard other left-leaning professors rant about close-minded (and racist) people who vote Republicans.
My anecdotal evidence indicates (as a libertarian leaning individual in academia) says is that within academia, those on the left are more likely to be closed-minded. It makes sense, because they don't get exposed to intelligent thinking by their intellectual opponents in personal interactions as often. If you're a leftist on a campus, your views simply won't get challenged too often.
Alternatively, perhaps I am just crafting a world view that makes me sound better. That couldn't possibly be the case, could it? :)