This is absolutely fantastic and fascinating. Always glad to see the continuing transition of libraries from physical to digital. Also, imagine the potential for a mashup between this and the current/historical Street Views available on Google Maps.
You can read more about this project on its about page: <a href="http://www.oldnyc.org/about.html" rel="nofollow">http://www.oldnyc.org/about.html</a>
I love this -- great way to visualize these images.<p>Also, looks like <a href="http://old.nyc" rel="nofollow">http://old.nyc</a> is unregistered :)