I am not so sure - I would check with an accountant, I think you have to be incorporated in order to use pretax dollars for a retirement funding, with out it you save with after tax dollars,Eddy - are you a solo op? What are you planning to do: mow, apps, etc?
All an LLC will do for you over a simple sole prop is limit your personal liab. to business debts, suits, etc. General Liability insurance coverage will provide the same layer for you at $1mil, $2mil, or whatever limit you choose. You need GL anyway to do business, so then the LLC isn't actually doing much for you at all as long as you stay away from debt.