Apple today announced that it has added Soundgarden to the concert lineup for its new iTunes Festival at SXSW in Austin, Texas next month [iTunes Store]. Soundgarden will headline the March 13 concert, with supporting acts yet to be announced. As noted by The Loop, Soundgarden will play its landmark Superunknown album in its entirety, celebrating 20 years since the album's release. An expansion of the long-running iTunes Festival held in the UK each year, the SXSW concert series was announced by Apple last week, but at the time performers were announced for three only of the five da
