I once owned an AB Business many years ago, had a partner who thought it would be cute to take the business and run, litteraly. Anyways, I know this is a rather old posting but hope the information helps.
First you have to go to your local City Hall, file for a Business License (usually around 45.00).
Second you have to contact the IRS and request a TIN (Tax Identification Number).
Third depending on your State, County, and City, laws, you may have to file for a State,County,City TIN.
Fourth, find manufacturers that make the products you want to sell or make them yourself.
I know of a few places that sell AB things, but they only sell B2B, no resale or public wholesale.