We are a non-profit workforce development program that helps people get
re-employed.  We get paid for our efforts when we can document that
our participant has gotten a job. Problem is that some people will not
tell us where their job is, for reasons sometimes rational and
sometimes nutty. So - the question is:  how can we find out where a
person is working if all we know is the person's social security
number? Are there companies, on-line services or research tools?

Some of the information here may be of interest:

http://answers.google.com/answers/threadview?id=521356