Mendeley is a web application that helps you collect, manage, and cite research sources. It's easy to use, accessible within your web browser and/or on your desktop, and best of all it's free. Mendeley allows you to organize, annotate, and highlight PDFs, add to your citations, organize them into collections for different projects, and create bibliographies using Word or OpenOffice. It is available to use in any web browser and surprisingly powerful. Mendeley also has a downloadable desktop application for your Mendeley library.
The easiest method to start using Mendeley is from your favorite web browser. Sign up for a web library and/or download your Mendeley library directly to your desktop from the Mendeley homepage by clicking on the download button in the top right-hand corner. Then install the Mendeley browser extension for Chrome, Firefox, or Safari. Documents can be downloaded to your desktop Mendeley library, and you can sync your desktop library and your web library with one click.