I've tried a little bit of this myself, it isn't always as easy as it would seem as it's hard to set yourself in exactly the same spot as the photographer. My last attempt is here.

Someone else has tried and they've done it a heap better than I have as they've overlayed the pics and added a slider effect, where you can drag the old picture across the new one, click this link and you'll see what I mean.

"The idea was to revisit historic photograph locations and take identical photographs, as if the camera never moved and the world changed around it."

Watuga Hall
Hillsborough St