Check out this collection of historic World War II posters from the Cincinnati Digital Library. This collection of over 85 World War II propaganda posters are from both the U.S. and other nations. Since they are digital they can be downloaded and printed for use in the classroom. History teachers should race on over to this site ASAP.
The Vintage Ad Browser is a website that features a huge collection of over 100,000 old posters and advertisements from as far back as the 1700's. Their home page identifies their 53 categories and when you click on one it automatically takes you to the oldest ads from that collection. Within each category, you can navigate by clicking on the pages or if you want to go to a different date you can choose one of the decades that run along the top of the page. Looking at vintage ads is a good way to learn about a particular era and to compare eras as well. History teachers will be glad to hear that the website has a large selection of propaganda posters from the 1800's up to the 2000's but note that most of the posters after the 1940's are from Communist China. If you teach social studies then do yourself a favor by checking out the Vintage Ad Browser.