Sometimes the headlines just write themselves! The Peace Corps has announced a new digital library at http://collection.peacecorps.gov/ that is actually still in progress — the 50th anniversary of the Peace Corps is in 2011 and the organization is planning to continue to develop the library as that anniversary approaches.
At the moment the site contains a variety of archival materials, including digitized newsletters and speeches; posters, video clips, and other marketing materials; and stories and photos from current and returned volunteers. (The Corps is still soliciting materials from current and returned volunteers.) Content on the site starts in 1961 and continues to the present.
The advanced search page lets you search by keyword while specifying specific parts of the collection. I did a search for commercial and got 112 results from several different types of media, including newsletters, congressional materials, brochures, and even a volunteer application from 1968. Results are presented in sets of thumbnails, and everything I looked at — brochures, newsletters, and presentations to Congress — were available in full-text form as PDF documents.