Apple will likely unveil new iPhones on Sept. 12
       iPhone users awaiting the arrival of Apple's next-generation smartphone now have a date to circle on the calendar.   Apple ( AAPL , Tech30 )  will hold its annual product launch -- where it typically shows off new  iPhone models and other product updates -- on Tuesday September 12.     For the first time, the event will be held at the spaceship-shaped  Steve Jobs Theater on its new Cupertino, California headquarters,  expected to open later this year.  This year is expected to be a  big one for Apple, since 2017 marks the 10-year anniversary of the  iPhone. Rumors indicate the company will introduce three new devices at  the event: the iPhone 7S, iPhone 7S Plus and the so-called iPhone 8,  which will be the 10th anniversary edition.  The iPhone 7S line is expected to feature incremental updates, but the anniversary phone could get a whole new look.  Related: Fitbit tries to catch up to the Apple Watch       The invitation sent to members of the press.   Apple CEO Tim Cook wa...