Also, one thing to note about types of business structures. Partnerships have no liability limitations. If a partnership were formed and then sued by someone and the other party won, the registered partners would be fully liable for the suit. That means that if the partnership didn't have the funds, liquid assets, or convertible fix assets to cover the suit, the personal property of the partners would be taken, i.e. houses, cars, etc. A corporation is just the opposite in many ways. There is limited liability, but if say one day everyone decided they weren't interested in the company anymore, you can't just walk away and that's that. There are financial liabilities involved. You'll have to register officers, declare ownership and percentages, etc. If one person decides to walk away, the other partners can sue, offer a buyout, and other options. An example of this happening would be what happened at Orange County Choppers and the long lawsuit Paul, Sr. filed to force Paul, Jr. to sell his shares at what was a reduced market value.
I would suggest either an LLC or S-Corp. The liability protection of a corporation, but the ability to scale back and/or shut down if the decision is made that the direction isn't in-line with the vision, etc.