Falling out of F-1 status is not a crime, but you will no longer be in valid non-immigrant status and may be arrested and removed from the US. If you qualify, you can apply for a change of status to an employment-based visa but you cannot work legally until your application for change of status has been granted. The application is normally filed on form I-129.
Answered on Jun 11th, 2013 at 11:18 AM