Richard Florida, the thinker who's latest book, "Who's Your City?" (see my review, Find Your Place in The Economy), dovetails with this new study, reproduced the agreeableness map in his Geography of Personality post. He also includes links to a PDF of the research paper and to a number of blogs that commented on the study.
In other words, hire your customer support people from places like Nebraska and the Dakotas, home to sociable folks. Okay, that's facetious -- not every Nebraskan will be friendly, any more than all New Yorkers are neurotic. But it may be worth locating call centers in a region that tends to have sociable people.