In what ways do psychological processes and the natural and man-made physical environments interact? 

Environmental Psychology
Environmental Psychology - Good explanation of the field, with definitions. 
Current Trends in Environmental Psychology - Gary Evans's page. 
Environmental Psychology Home Page - Don Miles's page with links to research and information. 

Community Psychology
Community Psychology Network — Matthew Cook's resource for professionals, students, and others interested in learning about community psychology, research, and action.  Includes links to a large variety of discussion lists. 
Crucial Issues in the Field of Clinical and Community Psychology - Victoria del Barrio 
 

Relevant Discussion Groups
COMPSYCH - Community Psychology Listserv 
sub COMPSYCH your name 
COMMUNITY-PSYCHOLOGY - 
SUBSCRIBE COMMUNITY-PSYCHOLOGY your name