Ad*Access: Over 7,000 U.S. and Canadian magazine and newspaper ads from 1911-1955 in the categories of Beauty and Hygiene, Radio, Television, Transportation, and World War II propaganda. Earlier ads can be found in the companion site Emergence of Advertising in America, 1850-1920.
AdViews: A Digital Archive of Vintage Television Commercials: Thousands of historic commercials created for clients or acquired by the D'Arcy Masius Benton & Bowles (DMB&B) advertising agency or its predecessor during the 1950s - 1980s.
Adflip: Well-known American print ads from 1940-2001; full access to all ads requires payment, but a liimited number are available for free.
Advertising Archives: A selection of print ads from 1900-2010; most are UK or US with some Spanish and French ads.