WordNet (r) 3.0 (2006):

nitpick
    v 1: be overly critical; criticize minor details

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "nitpick":
   around the bush, beat about, beg the question, bicker, boggle,
   carp, catch at straws, cavil, choplogic, cut up, dodge, equivocate,
   evade, evade the issue, fault-find, fence, find fault, hedge,
   mystify, obscure, palter, parry, pettifog, pick holes, pick nits,
   pick to pieces, prevaricate, pull apart, pull to pieces, pussyfoot,
   quibble, shift, shuffle, shy, sidestep, split hairs,
   take exception, tear apart, tear to pieces, tergiversate