The Online Writing Lab at Purdue University provides easy to read and understand guides for different citation styles.
Use the menu on the left to navigate through the guide.
Zotero is "a free, easy-to-use Firefox extension to help you collect, manage, cite, and share your research sources. It lives right where you do your work—in the web browser itself."
Stony Brook University has a site license for EndNote, a bibliographic tool which enables users to quickly organize references while automatically building bibliographic documentation.
The library provides free EndNote workshops each semester. Check the library homepage for upcoming dates.