I've been working on a number of research projects lately (which explains why I haven't been keeping up with the mad posting pace of my colleagues here), and the open source Zotero Firefox plugin has quickly become indispensable. The idea behind Zotero is simple: it recognizes when you navigate to a page, like a journal entry or library catalog, with bibliographic content. Then it automatically parses out a bibliographic citation and lets you store it in a database. Zotero does a really great job of parsing out the bibliographic content, and if you want a screencap of the page or have full text of an article you want to attach, you can do that too. Once entries are in your library you can tag them, annotate them, and even add relationships between them. The capture mechanism is user-friendly, too: if Zotero finds a citation on a page, it adds a little blue book icon to the right-hand side of the address bar. Click it and the entry is added to your library. If it finds more than one citation--say on a the results page from a catalog search--it displays a folder icon, and clicking it will give you dropdown menu of checkboxes to select the items you want to add.
When you're ready to use your references, Zotero can format them and print them or save them to a file, or it can export them in any of a number of file formats compatible with BibTex and most major reference managers.
As you can see from the screenshot below, you do have to give up a little screen real estate when you have Zotero open, but for most people this should be a minor inconvenience. Hopefully a future version will have an option to make the Zotero pane a sidebar. All-in-all, though, I haven't found much beta in the Zotero beta.
