This is an outlier poll, and Zogby tends to be the least reliable of the major polls. (Actually I am a Zogby polling subject and just voted in one last night - I assume it will be published in the next week or so.)
It's not surprising that McCain would show a post-convention bump - the Republicans ran a very effective convention. Still, most major polls have Obama at a significant electoral-vote advantage, and my guess is that the debates will just enhance that. I would be surprised if this election is ultimately all that close.
As for Palin, I simply don't believe that she will, in the final analysis, look like a good choice. The bad news on her continues to trickle out (there WILL be stories this week about her extramarital affairs with Todd Palin's business partner - he just brought an unsuccessful motion to have the court records from his divorce sealed in a failed effort to keep this information out of the public eye), and if the Alaska legislature issues an unfavorable result in the Troopergate investigation, in October of all months, she will be a real liability IMO.