C-Span Election Pages – Campaign Ads also 2004
Campaign 2008: Ad Archive (Political Communication Lab at Stanford University) also 2006 ; 2004; 2003;2002; 2000; 1994
Factcheck.org Provides transcripts of ads and analysis of divergence from fact.
PBS – The :30 Second Candidate
ALLPolitics Ad Archive (older ad campaigns)
Air wars : television advertising in election campaigns, 1952-2004. Darrell M. West. CQ Press, c2005.
Mugar JF2112.A4 W47 2005 (2 older eds. available as well)
Political campaign communication : a bibliography and guide to the literature, 1973-1982 / by Lynda Lee Kaid and Anne Wadsworth. Scarecrow Press, 1985. Mugar Reference X Z7164.R4 K34 1985