To get on the *moderated* South Park mailing list, send an email to [email], and in the body of the message type only the single word "subscribe" (without the quotes and at the left margin; this is a command to a machine, not a person, so *don't* add a period or "please" or any other text, or it won't work).
Don't bother with the other South Park mailing list (Comedy Central's). As Prophecy pointed out here a few days ago, it's a disaster -- filled with angry bratty children yelling at each other (hmmm, sorta like the TV program) and people who *want* to unsubscribe but can't, so they complain endlessly and publicly on the list (which of course nobody in charge ever reads), which in turn just sends *more* mail to the list and its subscribers. It's only funny for a few minutes.