I wish to automatically assign the same contact as a Contact Role (and the same Role Name) to ALL converted when the deal is converted from a lead to a deal.  Would I use a Workflow Rule? If so, how do I do this?

For Example: The contact I would assign as a "Contact Role" would be "Bob Smith" and the "Role Name" would be "Realtor" for every Lead I convert into a Deal.

This is separate from the contact role that is assigned in the lead conversion process.