Yes in F1 status you can apply for work permit. Form I 765. Working without a valid work permit is illegal, but everyone does it, thats up to you if you wanna take risk or not. but when you apply for your workpermit, you dont have to mention that you've been working illegally without a work permit, that would be really dumb. INS- Deals with immigration issues. IRS-Deals with tax issues. Good Luck.