popacrobat
Rock n' Roll Doggie FOB
Honestly, I don't remember hearing much of the backing vocals when they did the song in Chicago. I didn't listen to the clip on U2.com, but they definitely weren't prominent in concert.
I know in New Jersey, he specifically says "On satellite, Sinead O'Connor!" and then she begins singing the "saw me coming..." bit. And she actually provides a backing vocal throughout the next verse, too.