HistoGrafica is a nice little site I learned about from the Classroom 2.0 forums (thanks Nancy B). It's a simple search engine for looking for old pictures for familiar places.
Have you ever asked yourself, I wonder what my town looked like at the Turn of the Century? Well, now you can find out by clicking here. It does interact w/ Google Maps and is very simple to use, just select your time range and click return.
Illinois Trust & Savings Bank - 1900 (sample)