I also heard of a courtcase, possibly the same one, where the band went away and recorded something to play for the judge, who could make no sense of anything until they gave him a sheet of lyrics, which had completely stupid things on, obviously it must be what Jim reffered to.

I've tried recording messages to play backwards, but it's really difficult, there is no way you could write a song that had one meaning in one way and a clear meaning in reverse.

One good use of reverse speaking though was in the film Top Secret, they filmed a scene backwards, including learning their dialogue backwards (which sounds strange even though they obviously tried hard), and it was quite funny.