Who do I & how do I report about the company who is filing H1b for foreign immigrants & using many fake documents.

USCIS: Immigration Direct (http://www.immigrationdirect.com/contact.jsp)

Depending on the nature of the fraud, you also might contact the Department of Labor (DOL), Wage and Hour Division (WHD) U.S. Department of Labor - Employment Standards Administration (ESA) - Wage and Hour Division (WHD) - H-1B Program (http://www.dol.gov/esa/WHD/immigration/h1b.htm)