Unfortunately, I don't know which ones specifically are good in that area. The sites below may help you find some free hotspots in New York. They also probably can give you some advice about which program you can get to war-walk if you decide to do that. I only do that with my Palm so I'm not sure about software for a PC.

http://www.wifinder.com
http://www.nycwireless.net
http://www.nodedb.com/unitedstates/ny/newyork/?