Remember, many online resources now provide citations formatted for your Works Cited or References page. Look for them when using databases and online encyclopedias.
Don't forget to include in-text citations too.
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."
The Online Writing Lab at Purdue University provides a good basic guide to the Chicago Manual of Style, including basic citation information.
Use the menu on the left to navigate through the guide.
The library has various style guides available to answer citation format questions.
A tutorial from Indiana University Bloomington that provides examples of plagiarism.