The cynical part of me says "They aren't getting past their prejudices because they've gotten to know Obama. They're getting past their prejudices because when somebody knows if it's the blue wire or the red wire to cut when disarming the bomb in the room, you don't give a rat's fuckhole what color they are."
Ah, but the disarming the bomb factor is huge -- HUGE even -- in getting people to see past their prejudices. People who still feel that way in fer-fucks-sake-2008 aren't going to give up their attitudes because they've decided that it's not philosophically tenable to be an ignorant twit, or that he's a good guy deep down, or anything else that requires self-reflection. But actually seeing that the world doesn't end does wonders.
Look at the effect of Truman's integration of the military in 1948, before it was very much on the map in civilian society. For that matter, look at the shift in attitudes toward DADT as more and more military and ex-military personnel have come out in the last 5 years or so. In both cases, people on the ground may not have been for change at first, but afterwards, there are any number of stories that go S/he was in my unit and s/he was solid, so I don't care if they serve... People don't always start on the path for the most high-minded reasons, but if they get there, I'll take 'em.
(I'd also say that not giving a rat's fuckhole about someone's color is a pretty decent working definition of getting over it. Doesn't mean that the transition stops there, but it's pretty good as a place to start.)