On the business side -
Look into what kind of company you want to start and laws / regulations with it.
LLC, Partnership etc. Fees, taxes so on.
Licensing ie TTB, state liquor, health and any other regulations.
Trademark could be considered as well.
Know your web stuff, if your going to out source or build your own site and everything goes with that.
Those are things worth reading and knowing. It could also change your mind all together.
I can go into a list of many more things that need to be done and learned but those are some of the big ones.
Learn to write a business plan and any other articles you may need.
Figure out funding. est costs. Learn your area for real estate.
Kick starter is something to look at and build a profile, supporting various projects so you look like you someone that isn't just looking for money.
Make a facebook page and build a following now with your homebrew.
Brewing -
Learn different systems. Nano, Mirco, what size. Vendors / Places to get equipment. Use / New / Custom
Find books or take classes etc on actually how to use the equipment.
Learn the science behind it. Couple good technical brewing sites that have good info or ways to purchase along with journals and technical briefs are the following.
http://www.ibd.org.uk/publications/brewer-and-distiller-international/
http://www.mbaa.com/
There is a lot homebrewers do not have to deal with in brewing that is crucial in a commercial environment.
Go on tours of breweries and have specific questions to ask about their operation or about equipment etc.
You could even call and see if a brewer will let you shadow (not volunteer) for a brew day.
I can seriously go on forever. Its a ridiculous amount of work. For actual things to read. Online has a lot of resources. State / Federal sites have what you need for a lot mentioned above. The two sites under brewing will give you a lot of good info to read and can point you in other directions to follow up on any reading. General business sites have a lot of good info. If you have a specific topic, search for it. Classes can be helpful, brewing, business, accounting etc. Its just hard to point you to a book that has it all. Its a lot of little things to be read independent of each other. Figure an outline of what you want to learn and then search and look for those specific topics.