What is the diference between a lisitng agent, selling agent and a dual agent regarding the sale of real property?

A listing agent reprensents the seller. A buyer would have his or her own buying agent. A dual agent will represent both the seller or the buyer.

In almost all cases, the brokers are paid by the Seller.  Before we had official recognition of "buyers' agent" all agents were considered the agents of the seller.  The problem is that the broker helps the buyer develop a negotating strategy to deal with the seller.  Before, the seller could make the agent reveal the discussions with buyer about negotiation.  Now, there is a difference.  lA listing agent can have confidential discussions with the seller and not reveal the discussions to the buyer.  A buyer agent can have confidential discussions with the buyer and not reveal these to the seller.  A dual agent has no confidential discussions with either buyer or seller.

Hong Shen is correct.  These real property agents are also known as brokers, and the difference is who they are representing, as between the buyer and the seller.  The big drawback of having a dual agency broker is that they represent two parties with opposing interests in the same transaction.  If you are looking for confidentiality obtain your own real estate broker/agent.