If so: http://www.youtube.com/watch?v=3tTHn2tHhcI
That is excellent, I think it comes from the 'Very Scary Solstice' CD the HP Loevcraft Historical Society released a few years ago.
My personal favourite is 'OH CTHULU!' sung to the tune of the Haleluya Chorus from Handle's Messiah.
http://www.youtube.com/watch?v=ZZAoLnn4LF0
I did a big multiplayer WW1 Chritsmas Skirmish game last year, one of the players had a character called 'Major Alester Crowley' who had a couple of non standard abilities, whenever he wanted to use them I'd play that bit realy loud ;D it gave all the players a fright ;D ;D ;D
"Oh, Cthhulu" sounds as if he comes from sunken Ry'leh with a sigil on his knee!