The Collaborative International Dictionary of English v.0.48:

Point man \Point" man`\, n.; pl. -men (-men).
   1. (Mil.) the lead soldier in a foot patrol under combat
      conditions.
      [PJC]

   2. a person who takes a conspicuous public position in
      proposing a new idea or initiating a new policy, who may
      become a target of criticism for those opposed. "The
      Secretary of State served as point man for the
      administration's new China policy."
      [PJC]

WordNet (r) 3.0 (2006):

point man
    n 1: someone who is the forefront of an important enterprise;
         "he is the president's point man on economic issues"
    2: a soldier who goes ahead of a patrol