A list of off site strategy resources of any kind for the game of Diplomacy.
http://www.wizards.com/default.asp?x=ah/articles Several good articles including some written by Edi Birsan that are very good for beginning players.
http://www.diplom.org/~diparch/resources/strategy.htm Tons of articles over several different topics relating to the game.
http://www.diplom.org/index.py Diplom's home page with links to many items and articles on a variety of subjects, including back issues of the Zine.
http://c.webring.com/hub?ring=diplomacy A diplomacy Webring starting point with over 60 affiliated sites.
http://realpolitik.sourceforge.net/main.html Realpolitik, a great site and they have an adjudicator you can play with to explore different moves in addition to the other offerings common to Dip sites.
http://en.wikipedia.org/wiki/Diplomacy_(game) The Wiki on Diplomacy full of history, discussions on scoring, variants, and a variety of good stuff in general.
http://www.whiningkentpigs.com/DW/tacal.htm The Tactics of Diplomacy by Allan Calhamer himself.
http://www.diplomacyworld.net/movies.htm Quicktime movies (4) which quickly and efficiently introduce new players to the game, orders, movement, special provinces, and adjudication. Created by Edi Birsan and a great primer to getting started playing the game.
List those you find useful or important and we will update the list for everyone's use and education.