Zotero is a great tool for collecting papers that you find on the web. It allows you to take a "snap shot" of a paper so you can edit it, quote it, create citations, and so on. There are two elements to Zotero; the website (www.zotero.org) and the Firefox add-on. You use the add-on to add papers to either the lab library or your own personal library, and you can sync your documents to the website. There are great tutorials listed on the right side of the website front page, and I've found the message boards to be helpful for sorting out errors, too.