Websites can be a useful resource when conducting research, but you have to make sure they fit the requirement of being a "credible source." Explore the following links to see how to evaluate a website.
Owl at Purdue - The go-to site for formatting in different writing styles (MLA, APA, etc.), as well as guidelines for writing papers
Diana Hacker - Great resource for the nuances of different ways to cite (MLA, APA, etc.)
Easy Bib- Let this great tool build a citation for you.
60 second recap- video based study guides of classic literature.
Barlett's Familiar Quotations Reference- quotes but also offers full text versions of some classics
Citation Machine- Formats in MLA, APA and Chicago Styles
Noodle Tools- Smart Tools. Smart Research. On the Web