Tell them straight up, "I stutter but it's not a hindrance to me whatsoever," and then go on to tell them the strength you have thanks to your stutter. Tell them it has made you appreciate the importance of speaking your mind, and of insisting that others do not interrupt or talk over you. You'll stutter your way through this, but they'll love you for it. After all, an interview is a time to brag about yourself - use your stutter to your advantage.