I've heard the Stairway to Heaven one. I believe I may still have the clip on my computer. Frankly, some of it sounds like actual words, but the rest is so unintelligable that it's more than a stretch to say there's a hidden message there. Even looking at what it was supposed to be saying while listening to it, I could only make out a few things that sounded like actual words. It was coincidence if you ask me, and people tend to read to much into it.

That said though, Satan does indeed rock. And he should with the souls of so many evil rockbands in his possession.