(Update: Gallup Tracking "Traditional" and "Expanded" Likely Voter models are weighted at 50%, so that the survey only counts once in the RCP National Average.)
Today's Gallup Tracking results have Obama ahead 51-44 and 53-43 among Likely Voters, and ahead 51-41 among Registered Voters.
RealClearPolitics is using an average of Gallup's two Likely Voters results in the RCP National Poll Average (Obama 52, McCain 43.5). Click here for further explanation.