3d tool to make an animation like this

Hello!
My name is Martin and I am a programmer who is trying to start making some simple 3d animations for my games. I work in ActionScript and I am used to work with vector and bitmap graphics but not with a 3d modeling tool.

I was wondering which is the tool or technology used by cityville to make animated avatars like this one:

Any ideas about how the two first images are created?
Some guidance will help me a lot to start trying to make something like this

Thank you!