RealClearPolitics has Obama leading McCain in polls from Gallup, Rasmussen, Newsweek, Fox and USA Today by an average of 6.8 points.
The Gallup and Fox polls (46-44 and 45-41, respectively) are probably within the margin of error.
Newsweek, though, has Obama up by 15 points, 51-36. I have no idea what conclusions one is supposed to draw from any of this.