U.S. Citizenship & Immigration Services (www.uscis.gov)
Formerly the adjudications division of the Immigration and Naturalization Service, now part of the Department of Homeland Security. Responsible for adjudicating various petitions and applications for benefits under the immigration laws of the U.S. through its four regional Service Centers and numerous District Offices.
U.S. Customs & Border Protection (www.cbp.gov)
The former inspections division of INS was merged with part of the U.S. Customs Service to create this new agency within the Department of Homeland Security. Responsible for inspection and admission of applicants for entry to the U.S.
U.S. Immigration & Customs Enforcement (www.ice.gov)
The former investigations/deportation division of INS was merged with part of the U.S. Customs Service to create this new agency within the Department of Homeland Security. Responsible for interior enforcement of immigration laws including workplace enforcement, and detention and deportation of aliens unlawfully in the U.S.
U.S. Department of State (www.travel.state.gov)
Responsible for the operation of U.S. Embassies and Consulates overseas which issue immigrant and nonimmigrant visas, as well as provide services to Americans traveling or living abroad.
Visa Bulletin (http://travel.state.gov/visa/bulletin/bulletin_1360.html)
Direct link to the monthly Visa Bulletin which summarizes the availability of immigrant visa numbers under the quota system on a monthly basis.
Immigration Regulations (http://goo.gl/touLD3 (shortened link))
Direct link to the regulations implementing the various provisions of the Immigration and Nationality Act and related legislation.
U.S. Department of Labor (www.doleta.gov)
Direct link to the Employment & Training Division of the Department of Labor which is responsible for PERM applications for Labor Certification as well as Labor Condition Applications to support H-1B petition.
Immigration & Nationality Act (http://www.uscis.gov/)
Direct link to the I & N Act of 1952, as amended.