You are going to want to file for for S - Corp. The difference between filling as a corporation and a sole - proprietorship (or partnership) is in the taxation and business ownership.
If you choose to be a sole proprietor then you personally are considered the financial entity of your business. This means that if your business is failing and the bill/tax collectors start a calling, they have a claim on all of your personal belongs, including your home. The good things about a sole proprietorship is the tax fillings are more simple, and you are only taxed on personal income.
Becoming a corporation is a little more of a complicated filling, but it seperates you from your business entity. This means that if you get sued for millions of dollars becuase you ran little Jimmy over with a mower, then they cannot touch your house and personal belongings. The downside is facing taxation at both the corporate and personal level. Your money gets taxed twice. I would consider this the best life insurance you can ever have. S - Corp is a filling for a small business where they can get around the double taxation. As long as your business is small (under 75 employees) then you can use this filling.
But like everyone else said. When you are in business you need your attorney on your right side and your accountant to on your left. Without these two your asking for trouble.