I agree with the above posts. Use a Client Service Agreement with included Independent Contractor language, not just an Independent Contractor Agreement. You are contacting with your clients as a business not as an individual. (Clients should be making payments to your company name, not your personal name.)
You should also supply your clients with a W-9. You can find a copy of a W-9 on the IRS website at:
http://www.irs.gov/pub/irs-pdf/fw9.pdf.
Your Client Service Agreement should also have a section with Confidentiality / Non-Disclosure language.
Julie