Apple's annual iTunes Festival has begun in London -- 30 days of free concents by top artists such as Usher, Jack White, Muse, and Alicia Keys. If you're not in London to attend the festival at the Roundhouse, you can watch all of the events via live streaming, or watch recordings after the concerts have taken place. Apple is making the shows available via streaminig to your desktop computer, to Apple TV, and via a free iTunes Festival app for the iPhone, iPad, and iPod touch.