Most of these sites give samples of citation for the selected style. None, however, should be considered to represent the complete style manual. 

Try the NCSU Libraries Citation Builder to construct proper citations (for a limited number of formats).  [Click Here]

APA:

APAStyle.org

A Product of the American Psychological Association. "The following is excerpted from the new 5th edition of the Publication Manual. The material provided covers commonly asked questions regarding how to cite electronic media." (Not the entire APA manual!)  [Click Here]

Using American Psychological Association (APA) Format

Information on this page is taken from The Publication Manual of the American Psychological Association (5th edition). (Not the entire APA manual!).  [Click Here]

CBE (Council of Biology Editors):

Documentation: CBE Documentation

From the Writer's Handbook, University of Wisconsin.  [Click Here]

Chicago/Turabian:

Documentation: Chicago Style

From the Writer's Handbook, University of Wisconsin.  [Click Here]

The Chicago Manual of Style FAQ (and not so FAQ)

From the manuscript editing department at the University of Chicago Press.  [Click Here]

Harvard:

Harvard Referencing

This information sheet shows the Harvard referencing style. A common scientific citation style.  [Click Here]

MLA:

Using Modern Language Association (MLA) Format

This is a handout from Purdue's On-Line Writing Lab.  [Click Here]

Others:

The Columbia Guide to Online Style

A selection of examples from this manual.  [Click Here]

Documentation: APSA Documentation

American Political Science Association. From the Writier's Handbook, University of Wisconsin.  [Click Here]

Excerpts from International Standard ISO 690-2

Excerpts of "Information and documentation -- Bibliographic references -- Part 2: Electronic documents or parts thereof."  [Click Here]

Uncle Sam: Brief Guide to Citing Government Publications

Based on Chicago. Extensive sample citations.  [Click Here]

University of Tennessee Guide to the Preparation of Theses and Dissertations

10th edition, 2003. Guidelines for graduate students.  [Click Here]

Vancouver Style

Uniform Requirements for Manuscripts Submitted to Biomedical Journals.  [Click Here]

Grammar & Usage

American Heritage Book of English Usage

"With a detailed look at grammar, style, diction, word formation, gender, social groups and scientific forms, this valuable reference work is ideal for students, writers, academicians and anybody concerned about proper writing style." From Bartleby.com.  [Click Here]

Elements of Style

The complete text of the 1918 edition of William Strunk's Elements of Style is available online. This important handbook covers the basic rules of English usage and principles of composition. From Bartleby.com.  [Click Here]

The King's English

By H.W. Fowler, standard English usage, circa 1908. From Bartleby.com.  [Click Here]

On-line Writing Lab (OWL)

This lab at Purdue University provides a wide range of documents on writing skills including punctuation, grammar, spelling, term paper writing, etc.  [Click Here]

Guide to Grammar and Style

A basic guide to grammar, style, and usage written by Jack Lynch, Assistant Professor in the English department of the Newark campus of Rutgers University.  [Click Here]

Writers' Workshop Grammar Handbook

Information about grammatical rules, writing techniques, and bibliographic formats. From the English Department of the University of Illinois at Urbana-Champaign.  [Click Here]