The conference venue is at Columbia University, located in the Morningside Heights neighborhood of Manhattan (map).
Hotels (all deals are now expired)
The Excelsior Hotel
The Lucerne Hotel
Hotel Beacon (Deal expired)
The short-term home rental service Airbnb is very popular in New York City. The city has cracked-down on illegal rentals in recent years; the company is now working to comply with city regulations.
ConferenceShare is a website that will help you find other conference attendees to share hotel rooms (or other accommodations).