Cyndi's List - A comprehensive, categorized & cross-referenced list of links that point you to genealogical research sites online.
National Archives - Resources for genealogists including census, immigration, military, and land records.
RootsWeb - A collection of search engines and databases, family trees, mailing lists, and message boards to assist with your genealogical search.
State Archives Referral List - A collection of web links and contact information for the state archive in each state.
U.S. GenWeb - Free genealogy resources with links to different states and counties.
Databases
Ancestry - Library Edition: Accessible from library computers only. Search immigration, military, and census records, birth, death, and marriage certificates, and more.
Family Search - Search for family records in various media forms, family trees, and more.