is it possible to rig and animate withing unity?

Is it possible to rig and then animate a character within unity3d?

I have seen all the functions that one would need to do so, but it's quite a bit of scripting and probably much easier to just use an external program.

It's much easier to just use Blender (if you're looking for a free solution), but start your search at Bone Weights if you're set on doing it in Unity.