Psychology 

Professional

American Psychological Association

• Scientific and professional organization representing psychology in the United States. It is the largest association of psychologists in the world. There is an entire section on careers in psychology and another section for students.
  

Association for Psychological Science

• Non-profit dedicated to the advancement of scientific psychology.

Psych Web

• Contains psychology related material for students and teachers of psychology.

Subject specific

Adolescent Risk Communicaton Institute (ACRI)

• Part of the Annenberg Public Policy Center. Its mission "is to promote healthy youth development by educating the public, scholarly community and policy-makers about the latest scientific advances in reducing risks to adolescent health. It does so by convening conferences of experts, conducting national surveys and performing externally funded research. The findings of these projects are communicated to both scholars and the public through books, scientific reports and on the Internet."

Annenberg Public Policy Center

• "By conducting and releasing research, staging conferences and hosting policy discussions, its scholars have addressed the role of communication in politics, adolescent behavior, child development, health care, civics and mental health, among other important arenas. The Center’s researchers have drafted materials that helped policy-makers, journalists, scholars, constituent groups and the general public better understand the role that media play in their lives and the life of the nation."

Mental Health (Medline Plus)

• A service of the U.S. National Library of Medicing and the National Institutes of Health.
• Covers a wide range of mental health issues including current research in the field.