WordNet (r) 3.0 (2006):

pitchman
    n 1: an aggressive salesman who uses a fast line of talk to sell
         something
    2: someone who travels about selling his wares (as on the
       streets or at carnivals) [syn: peddler, pedlar,
       packman, hawker, pitchman]

Moby Thesaurus II by Grady Ward, 1.0:

32 Moby Thesaurus words for "pitchman":
   ballyhoo man, ballyhooer, barker, bunco artist, bunco steerer,
   canvasser, cardsharp, cardsharper, carpetbagger, con artist,
   con man, confidence man, crimp, horse coper, horse trader, jackleg,
   land pirate, land shark, land-grabber, mortgage shark, pettifogger,
   shark, sharp, sharper, sharpie, shortchanger, shyster, slicker,
   solicitor, spieler, tout, touter