Here are some new additions to The Best Resources For Learning About The 2012 U.S. Presidential Election that are specifically related to campaign ads:
Political Communication Lab from Stanford has what appears to be all the video campaign ads from this and many past elections.
The Museum of The Moving Image has a similar collection.
Getting to Know the Candidates: Analyzing Their Campaign Ads is a simple but decent lesson plan from Education World.
How To Watch A Political Ad is from Annie Murphy Paul.
The Attack Ad, Pompeii-Style is from The New York Times.
Here are “60 Years Of Presidential Attack Ads In One Video”: