Recently some friends and I played Diplomacy online at http://www.playdiplomacy.com. It was fun to play a turn-based game with friends that pretty much can never manage to get into the same place at the same time. Particularly since we’re in four different states.
Anyways, playing was fun except for a terrible interface (it won’t tell you if you’re making an illegal move, so trial and error is the only way to find out) and the fact that playing reminded me that I really fucking hate the game Diplomacy.
So, has anyone got an recommendations for any similar game? Turn-based, online, multi-player?
-Joe
**This is about as far from diplomacy that you can get, but its turn based, online, and multiplayer, but I suspect it might not be what you are looking for.
Stone Age 2 has a …errr…stone age theme and a large map to explore.
Its similar to SNES and PS1 style RPG’s if that’s what you like…(I do!)
It’s free to d/l and play… more at http://stoneage2.aeriagames.com/
If that’s not what you want, check out http://www.kongregate.com/multiplayer-games
Kongregate is a site where developers upload new games…IMO there;s more than a few gems there, and it’s all free :D**
Kinda fun free multiplayer Turn-based fighting game: http://yamatotwinkie.mybrute.com
Not really a whole lot of strategy involved though 
Battle for Wesnoth has decent online capabilities. There’s an active thread for it elsewhere in the Game Room at the moment.
I wanted to recommend you play Diplomacy at http://phpdiplomacy.net/ It’s free, it has a very clean interface, and it only gives you the option of valid moves.
Have you tried Cosmic Encounter? It’s another board game that’s been “ported” to the Internet. It’s been a while since I tried it, but I know that it can be played for free, with additional options unlocked by paying.