The network is free as in `free speech' and `free beer'. Each access point is run independently by volunteers with their own equipment.
The NYC Wireless group has produced some outstanding content, including a Power over Ethernet HOWTO. They are also looking into the possibility of incorporating as a non-profit organization and offering resource distribution services to their members and other community groups. Their efforts haven't gone unnoticed in the popular press; they have even been featured on CNN for their work on setting up public network access.
They can be found online at http://www.nycwireless.net/, where they host a FAQ, mailing list, node map, and other resources.