From U2wanderer site:
American Prayer: Written by Hewson and Stewart. Performed by Bono, the Edge, Beyonce and David A Stewart.
So that is Bono and Dave Stewart. It was performed by the above artists at the 46664 concert in South Africa and Bono performed it accompanied by a boom box on the Heart of America bus tour that he did in 2002 through middle America to get people to work on the AIDS projects for Africa.
I don't know why but when they did it as a group performance on Idol last year someone in the press started reporting that Bono had written the song specifically for American Idol which was total bullshit.
Dana