Play-By-E-Mail

Steam Trek - Adventures in an alternate history where Queen Victoria is out to rule the solar system. Players become crewmembers of Her Majesty's Aethership Dauntless commissioned by the United Kingdom of Planets.
http://steam-trek.com/

KJC Games' Warlord - Post holocaust world using 20th century weaponry. Features rule book download.
http://www.kjcgames.com/warlord.htm

The Universe - Political, military and economic wargame. Players take on roles as key politicians and leaders in a human-dominated universe. Features details on the setting, factions, maps, rules, and an encyclopedia.
http://www.theuniverse.org.uk

Seraph Chronicles: Realm Wars - Galactic-based free form adventure. Features details on how to join, chronology, character roster, game rules, and contact information.
http://www.geocities.com/realm_wars/

Myst Reinterpreted - An alternate D'ni - Game set in the Myst universe, played using a rules-light system based on FUDGE. Background, rules, and instructions for joining are included.
http://www.angelfire.com/journal2/mystreint/

Heritage - RPG set in the near future, with a series of events stretching from Antarctica to Mars.
http://www.geocities.com/gil_laurence/Poussieres.html

Dune PBeM - An online play-by-email game based on Frank Herbert's "Dune". Players take on the role of a House in the Imperium. Rulebook, discussion forums and setting information.
http://www.dunepbem.tapirdesigns.co.uk/

Star En Garde - StarEnGarde is a free PBeM game combining turn-based orders and e-mail list roleplaying. The genre could be described as Buck Rogers meets Star Wars meets Hitchikers Guide to the Galaxy.
http://www.cooneysite.com/starengarde

USI-RPG: Unified Space Intelligence - Play by email game set 800 years in the future. Includes a detailed technology database, setting description, factions, races and a discussion forum.
http://www.usi-rpg.com

Joint Effort - In a prosperous republic, tobacco, alcohol, and other drugs have been made illegal. Play as a law-enforcement-officer, bootlegging dealer, or double agent.
http://space_wasted.tripod.com/joint.html

All Mother - Game set on a futuristic Earth-like world setting.
http://www.geocities.com/Area51/Quadrant/9278/main.html

Beyond the Stellar Empire - Features rules, maps, program information, guides, list archives, and the Ringbone Gazette e-zine.
http://www.beyondthestellarempire.com/bse/bseindex.asp