Talking to a reporter should be like dealing with a cop. Keep it light, but don't try to be funny. While humor often helps to relax a tense situation, joking with a reporter is not always a good idea. That great quip of yours might not seem as clever when quoted out of context.
Remember, the reporter is looking for you to "make news"–which could mean losing your temper or saying something controversial.
Forget everything you've seen in all of those movies about talking off-the-record with a muckraking reporter. Everything you say could be on the record, even if the reporter says otherwise; terms like "on background" and "off-the-record" are not legally binding.
The reporter does not need your permission to write or print anything you say, so don't share anything you wouldn't want to see on the web.
The reporter isn't the only one who can ask questions. Get as much information as you can about the complaint or issue the reporter is calling about. Listen and take notes, but don't try to argue the merits of the case right away. Let the reporter ask her questions.
Answer what you can, but don't feel the need to respond to everything right away. It is not unreasonable to request a day or two to look into the situation or gather information. That gap between conversation and deadline also gives you an opportunity to deal with, say, a customer complaint. By the time you get back with the reporter, the problem may no longer exist.