Hi Sharon,
I would suggest talking with your accountant or someone at the nearest
not-for-profit Florida Small Business Development Center for advice on
whether your son should set up a business.
http://www.floridatrend.com/small_biz_article.asp?aID=46835
If he does set up the business, here is information and the form to
receive a federal Employer Identification Number that he would provide
to customers instead of his Social Security number. He does not have
to incorporate to register for the federal EIN.
http://www.irs.gov/pub/irs-pdf/fss4.pdf
I hope that helps.
Barbara Miracle
Editor
FloridaSmallBusiness.com