Zotero (a great open source tool for managing bibliographies) recently announced the latest version of its  Firefox plugin, making it even better and allowing it to compete with commercial products like RefWorks.  The new features synchronize your databases between different machines and automatically backup your library data on Zotero’s servers.  A number of other smaller updates are also included such as support for proxy servers and rich text notes.

For more information on the upgrade read: Online Research: Zotero Moves Into the Cloud