The American Psychological Association (APA) web site contains a wealth of information. With links to PsychNET®, PsycINFO, PsychCrawler, and much more, the APA can serve as a one-stop research center.
The magazine of the APA of Graduate Students provides an abundance of information directed at graduate students. Undergraduates will benefit from this website too!
The Association for Psychological Sciences (APS) maintains an extensive web site, offering access to their archives, links to many other psychology sites, and up-to-date news and announcements in the study of Psychology.
This website provides links to other helpful websites with instructions on learning and using APA style.