The creators of Spore recently released the creature creator for spore. It's basically the same thing you would use in the game to create animals in the creature phase (one of the many phases of the game). You can either purchase it, or download the free trial here :
http://www.spore.com/trial
They only give you a few different versions of each body part you can use ( I think you start out with all of them when you purchase the game. I'm probably wrong though lol)
But with the really limited supplies they give you, you can make a hell of a lot of different creatures. You can arrange body parts however the hell you want. You have control over several aspects of a body part: you can make it longer, wider, change its position on the body, and much more.
I'm really looking forward to this game.