Well, the best entity to establish for the exclusive purpose of minimizing self-employment taxes is likely an S-corp, provided that you pay yourself and other owners (if applicable) reasonable wages. This, however, is not the only consideration to take into account. It may not benefit you until you get to higher income levels, and could hurt you in many other ways.
Depending on what state you are in, you should get an attorney who specializes in business formation to assist with your decision. And then talk to your accountant to see if the savings would be worth it.