I guess it depends on the context. So new people I'm meeting in person for the first time generally figure it out, no need to bring it up but if you are meeting up with someone for the first time in person but have talked previously (like meeting someone on a dating site or such) I let them know when we plan the meet up "Hey just so you know I do stutter, sometimes it's worse when I'm nervous" and then typically it's not a real awkward thing or at least for me...maybe I've been lucky, not sure