[3d UPDATE: South Park Executive Producer Anne Garefino confirmed to me that the clip is a forgery, but an uncensored episode does exist. See the details here.]
[2d UPDATE: I have had a call into South Park Studios for a while to try to get them to confirm or deny the authenticity of the clip. Until then, I find Brendan Loy persuasive that the clip is a fake.]
[1st UPDATE: A commenter below thinks that the clip and still photo might be fakes that have been photoshopped. Like some of the Danish cartoons, the clip linked here and the still photo might well be forgeries.]
[What purports to be] The censored clip of Mohammed from the Wednesday South Park episode may be viewed at the South Park Scriptorium (with the proper software). A still picture of Mohammed from the [purportedly] censored scene is also available there. [Brendan Loy has reasonably good evidence suggesting that they are forgeries.]
In the clip, Mohammed says:
“Ah, jihad, jihad.”
[Still photo deleted for reasons given in the 2d Update above.]
[If legitimate,] this clip tends to show (though it doesn’t prove) that, despite earlier warnings that Comedy Central would not allow Mohammed to be shown, Stone and Parker still hoped to change the network’s decision.