Virtual Religion Index Created by Rutgers University, this site covers many topics in the subject of Religion. Provides a good starting point for your research.
Pluralism Project at Harvard University The mission of this site is "to help Americans engage with the realities of religious diversity through research, outreach, and the active dissemination of resources."
Interfaith Calendar Lists sacred times for world religions.
Pew Forum on Religion & Public Life A non-partisan site that explores all aspects of religion in America and in world affairs.
Association of Religion Data Archives (ARDA) Housed at Pennsylvania State University, ARDA provides current statistics related to topics in religion in the U.S. and beyond.