The Collaborative International Dictionary of English v.0.48:

Innovator \In"no*va`tor\, n. [Cf. F. innovateur.]
   One who innovates. --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

innovator
    n 1: someone who helps to open up a new line of research or
         technology or art [syn: pioneer, innovator,
         trailblazer, groundbreaker]

Moby Thesaurus II by Grady Ward, 1.0:

58 Moby Thesaurus words for "innovator":
   agent, alterant, alterative, alterer, ancestor, announcer,
   antecedent, architect, author, avant-garde, bellwether, buccinator,
   bushwhacker, catalyst, catalytic agent, creator, developer,
   explorer, ferment, forebear, foregoer, forerunner, front runner,
   frontiersman, fugleman, groundbreaker, guide, harbinger, herald,
   innovationist, introducer, inventor, lead runner, leader, leaven,
   maker, messenger, modificator, modifier, original, originator,
   pathfinder, pioneer, point, precedent, precursor, predecessor,
   producer, scout, stormy petrel, trailblazer, trailbreaker,
   transformer, transmogrifier, vanguard, vaunt-courier, voortrekker,
   yeast