Very helpful New York City Map

The screenshot above is a portion of NYCity Map, an interactive map that brings a huge amount of information into one place. The portion above highlights the area around Stuyvesant Square, with the five closest wi-fi hotspots identified. You can search by address, intersection, community district, zip code. In addition to finding wi-fi, you can also find: greenmarkets, parks, schools, museums, hospitals and so on. The map links to building and property information, elected official information, and neighborhood information (polling places, hurricane evacuation zones).

And the map has historical information, with photographs from 1996, 1951, and 1924. Here's how the same area looked in 1924:

It's a great resource. Have fun playing with it.