These tools help you manage your citations and develop bibliographies.
Zotero is citation management software with a free desktop application with plug-ins for all major browsers to easily collect your sources. You can cite your sources in both Word and Google Docs.
The Zotero Tutorial will get you started and answer general questions.
ZoteroBib: Enter the URL, DOI, or ISBN and ZoteroBib will format a citation for you in the style you choose. No software required.
The CSB and SJU Libraries' Citation Help page provides information on official style guidebooks, useful online guides (like the Purdue OWL's APA Style page), and citation management tools like Zotero.
Besides the Publication Manual of the American Psychological Association, these sites offer online explanations and examples of APA style: