Historic Aerial photographs.
It doesn't have anywhere near complete coverage of the US yet, but my town is covered, and yours may be too. I can look at aerial pictures of my neighborhood in 1949, 1962, 1979, 2002, and 2003. It interesting to see what my neighborhood looked like before it was bisected by Route 66. All these streets that currently dead end at a sound barrier wall used to pass through and connect the neighborhood. You can even see the construction of the highway in the 1979 shot.
The site is not as good as Google Earth, but if you are patient, there's a lot to see there. And Google Earth won't take you back in time. There are lots of annoying watermarks, but if you pan around and zoom in and out, they will shift to different locations.