Each state has its own Department of Revenue that sets the rates of excise tax, sales tax, income tax, and other taxes. Most companies will only deal with business tax expenses from a single Department of Revenue, but if you are considering multi-state operations, you should take the time to get familiar with each state you will be operating in.
Researching your business tax expenses yourself is a great starting point while you're still considering how to start your business. If you are an operating business, this information may still be useful, but Deziner Software strongly recommends that you consult with a tax professional in your tax research.
Understanding the impact of taxes upon your business is critical to properly forecasting your company's finances.