Complete instructions on citing and useful information on writing style and content can be found in the latest edition of the Publication Manual of the American Psychological Society. We have multiple copies in the Library in reference and on reserve; it's also worth considering buying your own if you are in the social sciences.
Both PsycINFO and Google Scholar provide APA formatted citations for items in their results lists. In both locations, use the cite option.
The following tools allow you to collect book and article citations from the library catalog and databases and (using a plugin for MS Word) insert those citations into your paper in the appropriate format. Some of the tools make it easier to import citations from the catalog and databases than others.