Cindi's List has links to over 188,000 genealogical sites
RootsWeb.com is a site with helps for getting started in tracing your family, searchable databases (especially the Social Security Death Index), tools, message boards, and links to other sites.
Some of the materials available at RootsWeb.com and online-subscription based census images and databases are available from:
Genealogy.com The online census images offered by Ancestry and Heritage Quest are also available free through subscribing libraries.
US Gen Web has free access to information gathered by volunteers throughout the United States.
Find A Grave has information on 4.5 million grave records including photos of tombstones.
Repositories of Primary Sources has links to over 5000 web sites describing holdings of manuscripts, archives, rare books, historical photographs, and other primary sources for the research scholar.