CardCow.com is a cool site to look at old postcards. They sell the postcards, but keep the pictures online. We were able to find some old photos of Fort Worth and other places of interest to us. After you spend a little time figuring out the search engine it is a lot of fun.
I found CardCow while searching for pictures of the old Kon Tiki motel in California. Why the Kon Tiki? We lived there for a few months when I was in 2nd grade.