The guide has been officially endorsed by the Alliance for Computing and Writing and can be found at:

Essentially, citation is broken into 4 parts:

1. the author,
2. the name of the Web site
3. URL of the site
4. the last date in which the user successfully accessed the site.

Thus, if you wanted to cite Walker's Guide, and accessed it last in March of 1996, you would write the following:

Janice Walker, "MLA-Style Citations for Electronic Sources." [http://www.cas.usf.edu/english/walker/mla.html], March 1996.

Because so many Web sites tend to be ephemeral and short-lived, it is crucial to site the date in which you last accessed the page.