Protection of your personal information is important whether you are a small sole proprietor business or a corporation. The solution to this problem is to apply to the IRS for a Employer Identification Number (EIN). In place of giving someone your social security number, give them your EIN. There are instances where you are required to give an identification number if you do more than $600 per year of business with other businesses. This dollar amount is subject to change by the IRS. For example, if you do any work over a set dollar amount for a nonprofit, they are required to have your ID number which they have to report on their tax return or they may lose their nonprofit status. Consultants are also required to give their ID number to employers. Your EIN number can be used in place of your social security number for all business purposes which protects your private information.
Use the link below to apply for an EIN with the IRS. If you have multiple businesses or change your business name, the IRS does not require multiple EIN’s. Your original EIN is tied to your social security number for IRS purposes. You can apply and have your number to use within minutes. Be sure to print out your confirmation page with your EIN number. You can also apply by mail but it will take considerably longer.
http://www.irs.gov/businesses/small/article/0,,id=98350,00.html
This IRS page will answer any questions you may have. Press the “Apply for an EIN Online” link to apply. It is free, simple, and you will get the number quickly.