Congressional Research Service Report on Immigration Issues of the 109th Congress

Information from Thomas.gov about HR4437

INS (Immigration and Naturalization Service) - Laws, Regulations and Guides
(http://uscis.gov/graphics/lawsregs/index.htm)
This comprehensive site is the Immigration legal page, providing information on regulations including the interpretation of legislation controlling immigration. Included is section 8 of the Code of Federal Regulations and the public laws amending the INA.

Migration Information Source
(http://www.migrationinformation.org/Feature/display.cfmFID=333) A searchable database that will take you to commentary on proposed legislation.

Federation for American Immigration Reform (FAIR) - (http://www.fairus.org/site/PageServer)
This non-partisan group provides information about immigration issues.
Has a section on policy and legislation:
http://www.fairus.org/site/PageServer?pagename=leg_legislationmain/ includes analysis explaining the potential impact of the legislation.