DAIDE - Diplomacy AI Development Environment. Developers' centre with information, news and download page. - http://www.daide.org.uk/index.xml
DipTool - Java programme which reads results from judges (or imports games from floc.net) and displays the maps. Connects to POP3 and sends orders using SMTP. - http://www.hagenah.de/diptool/
David Norman's Diplomacy Pages - Mapper for Windows, MapMaker, variants, DipTimer and Diplomacy AI. - http://www.ellought.demon.co.uk/
Automated Online Mapper - Observes games and produces maps automatically. Easy-to-use web interface. Powerful searches of the JDPR data base. - http://www.floc.net/
jDip - Adjudicator and mapping program that runs on Windows, Linux, Solaris, and Mac OS X. - http://jdip.sourceforge.net/
War Room - Will help you plan and play a complete game. Lets you add, remove and delete units outside the normal game rules. This helps you consider different strategies and plan campaigns without having to work through a complete game. - http://www.viago.net/Paul_Martinsen/WarRoom.html
Realpolitik - A cross-platform tool for displaying, adjudicating and tracking games and variants. Features downloads, manual, and forums. - http://realpolitik.sourceforge.net/
A Diplomacy Map for Computer Displays - It is topologically equivalent to Avalon-Hill's map. It is on a uniform grid with vertical and horizontal lines. All land regions are strictly rectangular. - http://www.crockford.com/wrrrld/diplomacy.html