Blender is an open source (formerly a commercial package) 3D creation suite. You can create both static and animated 3D characters and worlds. Note: this is a complex piece of software that will take time to learn. Check out the website to see what amazing things can be created using this free software.
Ade's Comments:
I haven't used it much - had a quick look round and did a tutorial. It is an impressive piece of software. Check the blender website for some of the wonderous animations that have been created with it my many clever souls!
