PscyhCrawler - from the American Pscyhological Association
http://www.psychcrawler.com

Psychology Gateway - from Social Science Information Gateway (SOSIG)
http://www.intute.ac.uk/socialsciences/psychology/

Classics in the History of Psychology - Developed by Christopher D. Green, York University, Toronto
Includes about 25 books and 200 articles and chapters which are in the public domain.
http://psychclassics.yorku.ca

Intute:  Social Sciences - Psychology
EXCELLENT advanced search feature!
http://www.intute.ac.uk/socialsciences/psychology/