MLA Style (MLA's web site)
Provides some FAQ's; however, this site does not provide the full style manual online.
MLA Handbook for Writers of Research Papers (6th ed.)
Olin and Uris Libraries Z253 .M68 2003 (located at the Reference Desks) APA Citation Style
Once research involves lots of sources and lots of pdfs, most people find using citation management/pdf organizing software saves time and energy.