For the next version of the FAQ, we really need to put together all the information about who does the voices for each of the major characters: Stan, Kyle, Cartman, Kenny, Wendy, Mrs. Cartman, Jimbo, Ned, etc.
Preferably, it should also be noted which characters' voices are computer-manipulated. With Stan and Kyle, it's obvious. With Cartman and Wendy et al, we don't know for sure.