The following has been prepared by Colin R. Singer, Attorney At Law, for the intended reference by interested individuals and is not intended to create an attorney-client communication. This writing may be reproduced for the personal non commercial use of interested individuals on the express or implied condition that the contents herein are neither edited, modified nor altered in whole or in part, directly or indirectly without the express written consent of the author herein. ( USA Immigration & Employment )

In order to legally work in the United States, you must have authorization from the INS. This comes in the form of a visa, or a change to a legal status which permits employment.  Employment visas are generally employer specific, in other words, you cannot change employers without reapplying for permission from the INS.

Generally, the first step is to find a job.  All the employment based visas require evidence of a job offer before a request for an employment based visa can be submitted.