Church of Reality 
Dedicated to understanding reality the way it really is.
http://www.churchofreality.org/Ethical Atheist
Group resisting religion's influence while promoting a scientific and nonreligious worldview.
http://www.ethicalatheist.com/
Atheist Alliance International
Organization of religion-free groups and individuals around the world. Aims to promote democratic, atheistic societies. Includes essays, information about conventions and publications, and a directory freethought groups throughout the world.
http://www.atheistalliance.org/
