Check the IRS website for details of who can and who can’t get a social security number (SSN). If you aren’t eligible for a SSN and intend to do business in the US as a non-resident foreign alien, you can apply for an Individual Taxpayer Identification Number (ITIN) which can be used when applying for loans etc. Link to the IRS site:
http://www.irs.gov/individuals/article/0,,id=96287,00.html