Starport: Galactic Empires is a free online space game for Windows. Starport is a massively multiplayer game meaning you play with and compete against many other players from around the world. Your life in the Starport universe will be filled with the excitement of battling other space captains for control of the galaxy, joining up with allies to run giant multigalactic corporations, and colonizing or invading vast new worlds to expand your empire. Paragon of justice or villainous space pirate? The choice is yours!
Official site: http://www.starportgame.com/