RealClearPolitics has the Quinnipiac Ohio poll:

• General Election Match Ups
  Clinton 44 - Giuliani 42
  Clinton 40 - Giuliani 35 - Bloomberg 10
  Clinton 45 - McCain 41
  Clinton 47 - Thompson 38
• Republicans
  Giuliani 24 (-1 vs. last poll in June 18-25)
  Thompson 18 (+1)
  McCain 14 (-2)
  Romney 8 (+1)
  Gingrich 5 (-1)
  Undecided 20 (-2)

But far more people have heard of Giuliani than Thompson:

• Favorable/Unfavorable Ratings
  Giuliani 50/27 (+23)
  Obama 45/22 (+23)
  Edwards 46/29 (+17)
  Thompson 30/13 (+17)
  McCain 40/31 (+9)
  Clinton 49/42 (+7)
  Gore 47/41 (+6)
  Bloomberg 17/20 (-3)
  Romney 15/19 (-4)