EDIT: I was just listening to Pop Muzik from my less-than-stellar copy of the Santiago show (and if you want to talk about intro music that gets the crowd pumped for a show...) and I noticed something. The person singing the lyrics sounds like Geddy Lee from Rush.
RE-EDIT: Speaking of Pop Muzik: Was the version of Pop Muzik that the band used as their intro music ever released? I know that there was a 9-minute mix on the Last Night On Earth single, but that has Bono performing the song. The version used during the shows has the original singer, M (Robin Scott), performing.