LWVUS:   www.lwv.org

The Migration Policy Institute: http://www.migrationpolicy.org/

Websites for US immigration policy info:
www.uscis.gov , www.ice.gov and www.state.gov

US Census Bureau: http://www.census.gov/prod/2004pubs
This will take you to a publication called “The Foreign Born Population
in the United States, 2003”.

The United States Immigration Support is the leading publisher
of legal books and immigration guides.
http://www.usimmigrationsupport.org

Pew Hispanic Center:
http://www.ime.gob.mx/investigaciones/pew_hispanic_center.htm