Helpful Websites:

The Statue of Liberty - Ellis Island Foundation
The Ellis Island Archives contains the passenger lists of more than 51 million immigrants, passengers and crew members who came through Ellis Island from 1892 - 1957.

Cyndi's List
A comprehensive, categorized and cross-referenced list of links that point you to genealogical research sites online.

The Newberry Library
The Newberry Library in Chicago has a rich collection of family histories, local histories, censuses, probate, deed, cemetery records, genealogy guides and reference works. Before you visit, read about their holdings.

Find a Grave
Search 105 million volunteer-transcribed grave records by surname or by cemetery.  Entries may include names, birth and death dates, and possibly a photo of the deceased.

GENUKI
GENUKI provides a virtual reference library of genealogical information of particular relevance to the UK and Ireland. It is a non-commercial service, maintained by a charitable trust and a group of volunteers.
 
Illinois Death Certificate Index 1916-1950
This database provides listings of death certificates filed with the Illinois Department of Public Health between 1916 and 1950. As a result of 1989 legislation, that agency makes available for public inspection at the Illinois State Archives only copies of death certificates produced 50 years ago or longer (410 Illinois Compiled Statutes 535/24). The Illinois State Archives has determined that this website is an extension of its Reference Room services. In accordance with a policy agreement with the Illinois Department of Public Health, the Illinois State Archives will make the index to death certificates produced fifty years or longer available on its website.

National Archives
National Archives and Records Administration (NARA) is an independent agency of the United States Government charged with preserving and documenting government and historical records.

Cook County Clerk
Search over 500,000 naturalization permits filed with the court from 1871-1929.

BaSIA
The BaSIA project, or 'Archive Index System', was created for a wide range of genealogists and researchers of 18th-20th century Wielkopolska history (although it also contains older information). Through a user-friendly interface, it provides users with a database containing indexes prepared by volunteers, derived from materials stored, inter alia, in state and church archives. You can find the surnames of wanted people, links to scans, records and other information to identify families, places and basic facts about their history. The database is created using the ASIA application (Automatic Archive Indexing System), which primarily allows indexing archival files in a user-friendly way.

JewishGen
A free, easy-to-use genealogy website features tens of millions of records, research tools, and other resources to help those with Jewish ancestry research and find family members.

Steve Morse
This site contains tools for finding immigration records, census records, vital records, and for dealing with calendars, maps, foreign alphabets, and numerous other applications.  Some of these tools fetch data from other websites but do so in more versatile ways than search tools provided on those websites.

U.S. Citizenship and Immigration Services
The USCIS has naturalization files from 1906 to 1956.  Download the genealogy brochure for information on how to request records.

The Polish Genealogical Society of America
The Polish Genealogical Society of America, with headquarters in Chicago, was founded and incorporated in the state of Illinois on August 23, 1978. The Society exists as a national 501(c) 3 tax exempt organization to collect, disseminate and preserve information on Polish and Polish-American family history and to help its members use that information in their own research.