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.