just go to this website http://www.search-episodes.com/South_Park then click on the link which is in blue color then you have all the access to download south park episodes!

http://www.southparkstudios.com/

vixy.net, maybe? Or mediaconverter.org? You can watch them all at southparkstudios.com, though.

if ya got realplayer you can watch them at xepisodes.com or summin like that and download them off there