Columbia University’s Off-Campus Housing Assistance (OCHA) manages a database known as the Housing Registry, which includes available rooms and apartments in non-Columbia-owned buildings and sublets of units in Columbia-managed housing—go to registration page.  Prospective roommates can also post and search profiles on this site.  In addition, OCHA offers one-on-one counseling for your housing search, and is supported in these efforts by cooperative relationships with two New York City real estate/relocation agencies. For further online resources, download OCHA’s “Newspapers and Other Online Resources” hand-out (PDF: 3 pages).