Well those are quite different, I believe. South park is actually mostly 2D. There's a series of youtube vids on rigging something like that: Maya South Park Rig - Part 1 - YouTube
Triplets of Belleville I think uses some 3D with toon shaders. Do some searching on toon shaders or cel shading in maya. Not sure about the simpsons, but I think that's the same (toon shading).