I'd start with this book
http://www.allworth.com/ProductDetai...6&Show=ExtInfo
There are a ton of resources for starting your own business, search them out. Talk to others who are successful in the niche that you want to be your focus.
Tippy, if your friend is looking for proof that he owns the copyright to his composition in the event that someone else uses it and he wishes to sue for infringement, then that mailed envelope will be of no use. In order to sue for copyright infringement, the owner must have registered it with the Office of Copyright. If he is looking for proof that he owns the copyright in case someone else claims ownership and is suing him for infringement, then he is probably also out of luck since the other person will have already registered in order to sue him. He might want to check with his attorney about copyright registration.