business venture

My son David has been researching a new idea that he presented this past weekend to a gentleman who has made tens of millions of dollars developing Internet companies and then selling them. This is one David did all on his own. And, at the first meeting, he convinced the gentleman to partner with David on this new project.

So, now my son is asking me the questions that a lot of people ask when they start a business and need a business structure fast. What is the best business structure? What state should we incorporate in?