I was asked to come in for an interview during which my interpersonal skills, logic skills, and difference-spotting skills were tested. They talked to me to make sure I could handle the basic requirements of customer service, then gave me a few short quizzes to test logic, basic math, and difference-spotting (in lists of similar numbers). Although I was nervous about passing the quizzes, they told me later that I had done great and they weren't nearly as rigorous as I had expected them to be.
Not really part of the interview, but there was a drug test later on, too, so be prepared to lose a little hair.