Style Manuals

ACS Books Reference Style Guidelines - From the American Chemical Society, this page has examples of standard forms for several types of literature citations.
American Chemical Society (ACS) Citation Style for Internet Sources - This short page by Judy Lichtman of Penn State Lehigh Valley has examples of citations of common types of Internet sources in ACS style.
APA, MLA, Turabian, and Chicago Citation Styles - Also includes AMA (American Medical Association) style. This resource from the CW Post campus of Long Island University has examples which have the various parts of the citation color coded. An interesting approach.
APA REFERENCE STYLE - This guide by David S. Baker and Lynn Henrichsen at Brigham Young University is easy to use and has many examples.
APA Style Electronic References - Excerpted from the 5th edition of the Publication Manual from 2001 although the webpage states it will be updated "regularly as there are additions, changes, or clarifications to APA style."
Chicago Manual of Style - The Manual is now in its fifteenth edition. Visitors may register for free and search this latest edition.
Citation Guide - Turabian - This guide from Concordia University is based on the 6th edition of Kate Turabian's A Manual for Writers of Term Papers, Theses, and Dissertations (Chicago: University of Chicago Press, 1996).
Citation Guides for Electronic Documents - From the International Federation of Library Associations and Institutions, this page has an extensive listing of citation resources.
Citation Machine - This is an automated tool for proper citation format for books, web pages, magazines, interviews, encyclopedias, journals, newspapers and more from the Landmark Project.
Citation Style Guides - From the Seattle Central Community College Library, this site features Modern Language Association (MLA), Chicago (Turabian), American Psychological Association (APA), and American Anthropological Association (AAA) styles. Includes examples of specific citations including electronic reference formats and links to other sources explaining the citation styles.
Citing Music Sources - From the Music Library at the University of Western Ontario, this is a guide to citing music sources in essays and bibliographies. There are many examples using the Turabian citation style.
Citing Sources - From Binghamton University Libraries.
Citing References in Your Paper - From the University of Wisconsin Writing Center, this page covers several citation styles, including APSA, APA, Chicago/Turabian, CBE, and MLA.
Council of Biology Editors (CBE) Style of Documentation in Science and Mathematics - Examples of references for a source list appended to a paper.
Ethics: Creating Citations - A module of HSU Library's Research Roadmap.
IPL FARQ: Citing Electronic Resources - A comprehensive listing (compiled by the Internet Public Library) of web sites and books to assist you with citing electronic resources.
Learning Page of the Library of Congress-How to Cite Electronic Sources - The Library of Congress uses items from their own digitized historical collections to illustrate citation examples.
Manuscript Guidelines for The Journal of Wildlife Management - Citation styles in wildlife management.
ONLINE! Citation Styles: Index - This web site for the 2003 edition of Online! A Reference Guide to Using Internet Sources by Andrew Harnack and Eugene Kleppinger has chapters online which cover MLA style, APA style, Chicago style, and CBE style.
Rapidcite.com - Citation generator for MLA, APA and Chicago stylesheets.
Research and Documenting Sources - A very nice guide from Purdue University's Online Writing Lab which includes:

Sources: Their Use and Acknowledgement - From Dartmouth College. Gives examples of citations in 4 styles: APA, MLA, Science (AAAS), and Note Style of the MLA.
Uncle Sam - Brief Guide to Citing Government Publications - This page from the University of Memphis "provides examples of the most common examples of government document citations. These examples are based on the Chicago/Turabian standard bibliographic style and not reference-list form."