Actually, it is a little different when it comes to having a buyer's representation - strictly in NYC and I do believe this applies to Brooklyn as well.
Vast majority of legitimate brokers in NYC are members of Real Estate Board of New York. ( REBNY). According to REBNY 's rule/agreement their members work under the folowing model: Seller's broker represents the seller , the broker who brings the buyer automatically represents the buyer. About 90% of all transactions in New York City happen with 2 brokers. As long as your broker is a member of REBNY you have representation with all loyalties to you. I am pretty sure this does not apply outside of Manhattan and Brooklyn. Here is members on rebny weblink
http://www.rebny.com/members_websites_residential.jsp - Thu Jun 19 2008, 15:12