Zotero
(pronounced "zoh-TAIR-oh") is a Firefox addon that collects, manages, and cites research sources. It's
easy to use, lives in your web browser where you do your work, and best of
all it's free. Zotero allows you to attach PDFs, notes and images to your
citations, organize them into collections for different projects, and create
bibliographies using Word or OpenOffice. It is easier to use than RefWorks and surprisingly powerful.
Since it's a Firefox plugin, it automatically updates itself periodically to
work with new online sources and new bibliographic styles.
Zotero Guide
You can learn more about Zotero by readng the Zotero Guide created here at Baylor, or you can also see this great guide published by the Zotero developers themselves. Also available as a PDF.