In academic writing, it is important to cite your references - in other words, to acknowledge and document the authors' works which you have consulted and used in your own work. There are a number of different options for formatting citations. Certain bibliographic styles correspond to certain disciplines, and you often may have a specific style assigned to you for a project. However, the most important thing to remember is that your citation style must be consistent throughout a single paper.
This site contains an interactive tutorial that explains what plagiarism is and how to properly credit authors.
RefWorks -- an online research management, writing and collaboration tool -- is designed to help researchers easily gather, manage, store and share all types of information, as well as generate citations and bibliographies.