Zotero is a free citation management software. With Zotero you can save items (journal articles, books, web pages, etc.) as you do your research and than manage them later. Zotero also helps you easily create bibliographies in any citation style. You can download it and find out more at http://zotero.org/ . There are several versions of Zotero including standalone, web-based and a Firefox plugin. The beauty of all three is that they synchronize so you can access your work wherever you have access to Zotero.
When you find an article of interest, click the sheet of paper icon in the address bar to save the item to Zotero.
You can access Zotero by clicking on the logo in the bottom right corner of your Firefox browser. You can create collection folders of items under My Library. Items in a library folder will be listed in the middle pane. The information for a specific item will be displayed in the right-hand pane. Notice the tab for Notes. This can be used to add free-text notes about the item.
By adding the Zotero plugin for Microsoft Word, you can than click a button (first circle on left below), search for something from the item you want to cite, then have it automatically added into your paper. When you are finished writing the paper, you can then click another button (second circle below) and have it automatically generate a bibliography for you.