Google and Life Magazine have created a search-able database filled with millions of photos from the Life Magazine archives... it's a great reference tool, and the photos go all the way back to the 1860s... so essentially about 20 years after Photography was "developed"
It's a great looking database, with so many cool photos... and it's worth checking out. I'm a big fan of flipping through photo collections bound in a book... and this is essentially the same thing.
LIFE photo archive hosted by Google
Share some neat ones if you find any...