An energetic stunt of a movie that wants to make you sweat like it's 1974. Stu (Colin Farrell), a hyperkinetic media publicist, steps into an old-fashioned Bell Atlantic phone booth in midtown Manhattan. The phone rings and the voice at the other end engages him in a dialogue that culminates with a simple, taunting threat: ''If you hang up, I will kill you.'' For the rest of the film, Farrell stands in that booth, sweating and yapping, his cockiness warring with fear and finally giving way to it. Phone Booth fancies itself a kind of Dog Day Afternoon in miniature, but the caller is just a device, a petty hero's petty conscience paying a Twilight Zone visit. Besides, who in the '70s would have asked an audience to gaze with shock and awe upon the hollow sins of a publicist?