A new alternative to TerraServer for overhead aerial photographs is GlobeXplorer (http://www.globexplorer.com) who apparently has a deal with MapQuest (http://www.mapquest.com) to provide users with aerial photographs when you put your address in.

The resolution on these photographs was fuzzy, but you can zoom in more tightly - I could see my car as a black pixel on the side of the road. The pictures also have a little yearstamp on the lower left corner, mine said 2000.
addendum: I believe that MapQuest has discontinued with providing this service. However, you may find Microsoft TerraServer to be helpful - http://terraserver.microsoft.com/ it provided me with better maps than those that were at Mapquest.