Peter Gabriel is adding a Pittsburgh date to his North American tour, "i/o - The Tour."The Rock & Roll Hall of Famer will perform at PPG Paints Arena on Saturday, Sept. 23.Tickets go on sale to the general public on Friday at ticketmaster.com, following presales that start on Tuesday.The tour is in support of Gabriel's forthcoming album, "i/o," which will be his first album of original songs since "Up" in 2002.Gabriel has released three songs from the "i/o" album: "Panopticom," "The Court" and "Playing for Time."