Part of the job of being a researcher is organizing knowledge, which most of the time comes in the form of scientific papers. Doing a bibliography search can take a large amount of time, and organizing it in a proper way is even more complex.
Recently I spotted this application for MacOSX, Papers. It behaves in a similar way as iTunes, but instead of organizing songs and movies, it organizes scientific papers, allowing you to download them, track them, search them and produce a bibtex file of your collection for the LaTeX/BibTeX citation mechanism. It is not open source, and you have to pay for it, but I found the price reasonable for the features it offers, and the developers are very eager to answer your questions (I already contacted them twice to ask for new features, and they replied in a short time and with enthusiasm).
Please don't take this post as an advertisement. It is an opinion about a product I use which, honestly, is helping me considerably in doing my job. If you have troubles organizing your paper library, and you have a mac, it is something worth considering. You can also check other Reference management software and leave comments on your experience.