Some portion of the site are accessible for free. Other requires registration like the Ancestry World Tree. The California Death Index, 1940-1997 requires paid membership.
Vital Records Information
"This page contains information about where to obtain vital records (such as birth, death & marriage certificates and divorce decrees) from each state, territory and county of the United States. If you are looking for vital records from a foreign county, see the links to foreign vital records web sites."
Genealogy site of the Church of Jesus Christ of Latter-day Saints. You can research the church's vast records collections. Also, you can access the catalog of their library where material can be inter-library loaned through local Family History Centers.
National Archives and Records Administration (NARA) - Genealogy Page
Are available on this site: Federal population censuses, 1790-1840, Immigration records and naturalization records. They also give tips and resources on how to conduct a genealogy search.
"The USGenWeb Project consists of a group of volunteers working together to provide Internet websites for genealogical research in every county and every state of the United States."
National Genealogical Society
"Founded in 1903 as a non-profit organization, the National Genealogical Society is a membership of individuals and other groups from all over the country that share a common love of the field of genealogy."
UC Davis Library Online Reference Shelf
"Scholarly online resource evidence and records for use by genealogists and family historians".