Two hours before showtime at the 02, London's state-of-the-art big venue for music, Don Henley is answering e-mail in his dressing room on a laptop and watching political talk shows from America on his other computer, which is hooked up to a large HD television screen. Sweating off an attack of bronchitis, he is wearing a fat woolen hat pulled down to his eyebrows, a long woolen trench coat, sweatpants and battered work boots....