If you have the RealPlayer plugin you can hear streaming versions of "Kyle's Mom's a Bitch" in D Minor by Cartman, and "I'm Just a Lonely Jew" by Kyle.

I have Eric Cartman's version of "Oh Holy Night" in RealPlayer Streaming Audio, WAV, and in QuickTime Video.

And Ned and Jimbo do a number on "Oh Little Town of Bethlehem" in RealPlayer Audio, WAV, and Quicktime Video.