Darkworld is a massively multiplayer space based real time strategy game. Players interact with a world which is continuously active. A player can create ships, colonize planets, invest in techology, and engage in warfare.
foundation is a multi-player interstellar struggle for survival.
Mars, Land of No Mercy
Mars, Land of No Mercy is a turn-based strategy game setting on Mars during the early stages of human colonization. The player embodies the leader of a mercenary team, landed on Mars to take advantage of conqueror battles between the Worldwide Colonizer Corporations.
Really Rather Good Battles In Space
Really Rather Good Battles In Space is a real time strategy game with fleets of spaceships. It is a single player real time strategy game following the fall of the great Artilian empire. It features a short but relatively polished single player campaign, pretty (albeit 2d) graphics, spaceships, and explosions.
Zionist In Space
Zionist In Space is a text-mode (curses) multiplayer game like Konquest (a turn based strategy; you send ships from planet to planet to conquer them). Has better interface usability (e.g. it already has an auto-send feature and save/load functionality).