Apple's iTunes Festival is set to return this year, with a free gig every night in September being held at the Roundhouse. 2013's festival will see some big names take to the stage, including Justin Timberlake, Kings of Leon, Katy Perry, Lady Gaga and Paramore. You can't just turn up to see them, though, you'll need to get your hands on some tickets first. Here's how to win free tickets to iTunes Festival 2013.
