Via Marc Ambinder, the McCain campaign has released the ad that they're planning on running tonight opposite Obama's speech.
The ad is embedded below, but the summary is that McCain, speaking directly to Obama, congratulates him for his nomination on "this historic day".
My initial reactions are two-fold. First, to thank the McCain campaign for having some small amount of grace, or at least enough sense of self-preservation to understand the backlash from an attack ad. Secondly, that this ad is mainly aimed at the media, to provide a booster shot of McMaverickness, to reinforce a badly bruised brand. Expect Chris Matthews to get that tingle up his leg, now that the "old John McCain is back" or similar nonsense.
-dms