The Center for History and New Media at George Mason University has produced and released Zotero, a Firefox plug-in that helps you gather, organize, and analyze sources (citations, full texts, web pages, images, and other objects), and lets you share the results of your research in a variety of ways.
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I haven’t tried this out yet, but it looks like it is created with an Educational setting in mind. Will be interesting to see if it is useful in a multiple user setting like a computer lab or library media center.