Dawn Rennart of She'sTooFondofBooks.com has compiled a guide of bookstores and sellers in NYC for the upcoming BEA and Book Blogger's Conference. The new website, Spotlight on New York City Bookstores is meant to be used as "a self-guided tour of bookish delights in the Big Apple."
The site lists bookstores in each borough, their websites, contact information, and directions to the store. There's a link for booksellers to upload information on their stores. According to Shelf Awareness, the listings will continue to be updated after the May 2010 events.
If you need further directions to the bookstores or getting around any of the 5 boroughs, I recommend Hopstop.com