I sometimes mention it, especially if I'm having an off day and I know that I'm going to stutter badly during an interview. On the occasions where I did mention it, a few interviewers would quiz me on how I would feel my stutter would impact my ability to do the job. Most of the time though, they say that they don't mind. Ironically the only successful interviews that I've had have been when I don't mention it at all and just tried to answer the questions to the best of my ability.