I talk openly about it with anyone that I feel comfortable talking with about personal matters, who are also curious enough to enquire. When stuttering in conversation with strangers, I'll just try to confidently explain that I have a stutter and then change the flow of the conversation towards them. For instance I'll say "you'll have to bear with me, I've got a bit of a stutter. What is it that you were saying about X earlier?" Funnily enough I can usually say this part fairly clearly after a stammering fit as I've practiced it often