End Note Online
Endnote Online is a FREE tool that can be used to create and manage citations for all your research projects.
Zotero
A free, easy-to-use Firefox extension to help you collect, manage, cite, and share your research sources. It lives right where you do your work—in the web browser itself.
Zotero Introduction
A guide to using Zotero to collect, organize, and cite your sources.