Adherents.com
Adherents.com offers statistics and a wealth of other information about religion.
http://www.adherents.com/

American Buddhist Congress
The American Buddhist Congress offers information about the Buddhist faith.
http://www.americanbuddhistcongress.org

Association of Religion Data Archives
The Archives offers statistics, maps, and much more to those studying religion.
http://www.thearda.com/

Bible Gateway
Bible Gateway offers numerous versions of the Bible, with the ability to look up passages, do keyword searches, and search through a topical index.
http://www.biblegateway.com/

Blue Letter Bible
Blue Letter Bible allows the user to search multiple versions of the Bible, read commentaries, and much more.
http://www.blueletterbible.org/

Catholic Directory
Search the Catholic Directory for locations of Catholic churches in the United States.
http://thecatholicdirectory.com/

Codex Sinaiticus
View the oldest complete copy of the New Testament online.
http://www.codex-sinaiticus.net/en/

Crosswalk Directory
Crosswalk offers links to various resources for Christians.
http://directory.crosswalk.com/

Dead Sea Scrolls
Portions of the Dead Sea Scrolls can be viewed here.
http://dss.collections.imj.org.il/

Global Anabaptist Mennonite Encyclopedia Online
Learn about the Amish and related religions here.
http://gameo.org/

Internet Christian Library
Internet Christian Library provides information about Christian missions, literature, early church documents, and many other resources.
http://www.iclnet.org

Into His Own: Perspective on the World of Jesus
Into His Own offers portions of the text from the Dead Sea Scrolls, and other sources, lineage charts, historic sites, biographies, and much more.
http://virtualreligion.net/iho/

Islamic Society of North America
The Islamic Society of North America offers information about Islam.
http://www.isna.net

Jewish Encyclopedia
The contents of the encyclopedia, searchable and browsable, originally published between 1901 and 1906.
http://jewishencyclopedia.com/

Jewishnet
Jewishnet offers links to organizations, universities, and many sources of information about Judaism.
http://www.jewishnet.org

Patheos.com
Use Patheos.com to learn about religions, and find places to worship.
http://www.patheos.com/

Sacred Texts
The sacred texts of many major religions are available here, along with much additional information.
http://sacred-texts.com/