(Is this old? I hope not, because the search page doesn't seem to exist)
Urban Dead
Urban Dead is a simple, text-based MMORPG that puts you in the shoes of a citizen of Malton, a city under quarantine due to the outbreak of something terrible; the recently dead have risen again, and they seek nothing more than to consume as many human brains as possible.
The twist?
There are no non-player characters. Everyone you run into,
even the zombies, are all player characters. Want to play as a zombie? Go ahead, it's your call!
There are several classes you can play as, including cops, firemen, soldiers, scientists, and of course the zombie. Death is never the end; you can always rise again as a member of the living dead. Horrified at what you've become? Perhaps the good folks at NecroTech can bring you back from the undead.
I've been playing it for a while, and I've got to say that I like this game.