The Capital Community College Guide for Writing Research Papers according to the APA Style is a good place to teach yourself the APA style.

The University of Wisconsin's Writer's Guide offers instruction in formatting according to MLA guidelines.

Go here to investigate Turabian Style (A simplified form of the Chicago Manual)

You might also want to turn to the U of Wisconsin's Writer's Guide for an introduction to the CBE style.

The Bedford St. Martin's site brings together instruction in all the styles mentioned above.