Speaking of Faith - a weekly national public radio series and website.
www.speakingoffaith.publicradio.org

Cushwa Center for the Study of American Catholicism at the University of Notre Dame
www.nd.edu/~cushwa

The Pluralism Project at Harvard University - an ongoing research project/website on religious diversity in the U.S.
www.pluralism.org

American Academy of Religion - an international professional organization and website
www.aarweb.org
 
Association of Religion Data Archives - a database of ongoing data gathering on topics of religion in the U.S.
www.thearda.com

Belief Net - a site for articles and essays on inspiration, spirituality and faith from a variety of authors.
www.beliefnet.com