World Religions

religious groups:

http://www.patheos.com/Library.html

http://www.mnsu.edu/emuseum/cultural/religion/

http://www.adherents.com/Religions_By_Adherents.html

http://www.religioustolerance.org/var_rel.htm

http://www.pbs.org/edens/thailand/buddhism.htm (for Buddhism only)

http://en.wikipedia.org/wiki/Major_religious_groups