They state it's a once-in-a-lifetime exhibit, and I believe them! Indeed, the British Museum will host an exhibition on Qin Shihuangdi (China's First Emperor) and his legacy, including several of the world-famous terracotta warriors

This exhibition will last from September 13, 2007 to April 6, 2008. You'll have to book tickets (timed entry; £12 + booking fees), which you can already do from this page. Look also there for more information as it becomes available