Hunter College Library (chat and email) http://library.hunter.cuny.edu/ask_a_librarian.htm

Library of Congress
http://www.loc.gov/rr/askalib/

The New York Public Library - The Branches
http://www.nypl.org/questions/

The New York Public Library - Humanities and Social Sciences Research Library
http://www.nypl.org/research/eref/eref.cfm