http://tetragotchi.com/
It is still on invitation, but you can get in by requesting on the forum
It is an artificial life simulator, that was turned into a game
The creatures evolve for speed - but you control them (what to do, which direction, etc ...)
You basically set the instructions for the next 24hours
The purpose is to assimilate other players creatures, and become the dominant species
First 3d evosim I found that was made into a multi-player game
(it takes a couple of hours before your sim is born, until that time there is not much you can do, so hang on
- your creature starts evolving once it gets the first instructions )