Adherents.com Adherents.com contains headcounts and other data of over 4200 world religions, sects, tribes, denominations, faith groups, cultures, etc.
BBC Religion This site includes basic beliefs, holidays, history, subdivisions, locations, symbols, etc. for religions including Buddhism, Hinduism, Sikhism, Paganism, Christianity and Islam.
Godchecker.com This is a somewhat unconventional look at mythology, with over 2850 gods identified.
Islam and Islamic Studies Resource Professor A. Godlas of the University of Georgie maintains this site on issues, background, and basic tenets of Islam.
JewishEncyclopedia.com This site is the full 12-volume Jewish Encyclopedia, published in 1901-1906. Note, because of the publishing date, it does not contain information on the Holocaust or the state of Israel.
New Advent: the Catholic Encyclopedia covers the churche's and Catholic individuals' roles in history, arts, sciences, and philosophy.
The Pew Forum on Religion and Pubic Life In general, the Forum tracks and aggregates information and articles on religion and pulic affairs in America. Check out its mission on the About Us link.
The Pluralism Project at Harvard University The Project’s focus is World Religions in America—the definition of specific religious movements and their integration into American society.
Religions This BBC site has basic information on a wide range of world religions as well as links to articles on many.
Virtual Religion Index VRI is a comprehensive subject index that can also be searched by keyword. It's intent is to help students locate quality resources more efficiently.