You can get a social security number with you F1 or J1 visa.... I just did when I got my MSc. For example, if you work as a T.A. or R.A. you get a SSN.
If you get a SSN on a F1 visa, you are allowed to work as a T.A. for a limited number of hours - but as soon as full-time commercial job or 200k of business income is reported to that SSN, your visa turns into a ticket back home.
Good Luck!