It varies from state to state and city to city. It's a good idea to stop by your local chamber of commerce to get the current info needed for starting a business.
This thread is basically your exact same question and has a lot of good info: http://www.t-shirtforums.com/business-finance/t41285.html
This thread is basically your exact same question and has a lot of good info: http://www.t-shirtforums.com/business-finance/t41285.html