What is the best way to get local Realtors e-mail listings?

In larger markets there is often a Real Estate Board Association which usually has a non-member website that allows the public access to contact information. Of course there are state and national boards too. I highly suggest you send your info via snail mail (to their office addresses and their home address if possible) rather than easily deletable or filtered spam on their email. You have to remember that Realtors are inundated by dozens and dozens of companies trying to sell them stuff.