Zotero is an easy-to-use yet powerful research tool that helps you gather, organize, and analyze sources and lets you share the results of your research.
A Firefox extension, Zotero includes the best parts of reference managers ... and the best parts of modern software and web applications (like iTunes and del.icio.us), such as the ability to interact, tag, and search in advanced ways.
Zotero integrates tightly with online resources; it can sense when users are viewing a book, article, or other object on the web, and — on many major research and library sites — find and automatically save the full reference information for the item in the correct fields.
Since it lives in the web browser, it can effortlessly transmit information to, and receive information from, other web services and applications; since it runs on one’s personal computer, it can also communicate with software running there (such as Microsoft Word).