1. Chart Beat: Katy Perry, Leona Lewis, Coldplay

    July 03, 2008 12:00 AM EDT Fred and his readers discuss Katy Perry, the first rock song, Leona Lewis and more! TIME FOR A CHANGE? Dear Fred, It is a significant achievement that Katy Perry has achieved the rock era's 1000th Number One single on the Billboard pop charts with "I Kissed A Girl," which -…