Introduction. Covers the authorship, date, origin and destination, its purpose and also talks about its relationship with the other Gospels. In outline form.
http://www.bible.org/docs/nt/books/joh/joh-intr.htm
Web site links and a bibliography of books and journal articles related to the Johannine Literature. By Armand J. Gagne Jr.
http://www.fourthgospel.com/