According to Rasmussen:
The Rasmussen Reports daily Presidential Tracking Poll for Wednesday shows President Obama attracting support from 46% of voters nationwide, while Mitt Romney earns 45% of the vote. Four percent (4%) prefer some other candidate, and five percent (5%) are undecided.
The president received a modest convention bounce, but that’s now gone. On the day the conventions began, Obama was up by two points. Now the numbers are essentially back to that starting point with the president leading by a point.