Most states are VERY stringent about what you have to do in order to sell raw milk. I live in Wisconsin and it is completely illegal to sell raw milk. I do have people that buy it for their pets - what they do with it when they take it off my property is their business.
I love having my own cow and the dairy products that we enjoy here at home, but would have to have a grade A dairy and a commercial kitchen in order to sell cheeses, butter, yogurt, etc. legally. Even with a grade A dairy, farmers in Wisconsin cannot sell raw milk for human consumption.
Check with your state's ag department to see what you need to do to be legal, as they are all different.