NewtonPA.com

I found this cool site one night while surfing.
It features free aerial photos of almost anywhere in the US. Also USGS maps which show elevations etc.
Note, the photos are several years out of date but still pretty cool.
All you have to do is punch in an address.  You can also zoom in or out with the grid on the left, or move in any direction.
The site address is;

http://terraserver-usa.com/advfind.aspx