Applying for a Tax ID (EIN) is pretty simple and can be done online during the week by visiting: http://www.irs.gov/Businesses/Small-Businesses-&-Self-Employed/Apply-for-an-Employer-Identification-Number-%28EIN%29-Online

Doing so will enable you not to have to use your social security number when you have situations that ask specifically for a business ID, like doing business with other parties or for billing certain entities.

The bigger issues are what kind of "tour" business are you talking about? Not knowing what state you're in, there might be local or state laws regarding the kind of business you're looking to perform that you'll want to be aware of. I read this as "tour" for musicians, but if you're talking about taking people on tours around a certain area, there will be a variety of liabilities that you'll want to ensure you're protected from in the event something happens.

Hope this helps get you started.

Anyone can start a business overnight by simply creating a sole proprietorship. A sole proprietorship is a business conducted without the use of a legal entity, such as a corporation or LLC. You won't need a tax ID to start your business, but you may need to provide your social security number in order to receive payments for your services. Your customers will be required to collect an IRS Form W-9 from you before they can remit payment. The information on the Form W-9 is used so they can accurately complete and File Form 1099-MISC with the IRS. If you don't have an EIN, you'll have to provide your social security number on the W-9. It's highly recommended that you form a legal entity to conduct your business, for both tax and liability protection reasons. Your individual facts and circumstances will determine what type of entity is best suited for your business needs (e.g. corporation, professional association, LLC). A business license may be required as well, depending upon what locations you are conducting business. Most business licenses are issued at the state and local level, so you'll have to check the county in which you live, as well as the counties you will be traveling for your tours.