I came across Historypin today and had to share it with you.  Historypin is a global social project.  People everywhere can upload their photos to the the Historypin map enabling users worldwide to search locations and view historical images.  Curious about Cincinnati street views both past and present?  Take a look here.  You can change the year to limit your results to a certain era.  Is there something missing from the map that you can contribute?  Get involved! Check out what archives in New York and Philadelphia have contributed so far.