Yes, he did die according to wikipedia on their entry in The Dark Knight. Which explains his funeral and the whole idea of Batman becoming pursued by the authorities. Towards the end, Batman and Gordon agree to blame the murders Harvey commited on Batman, and why Gordon is breaking the Bat-signal. Batman quotes "set the dogs on me" because the whole idea is that Harvey Dent was Gotham's shining light in the darkness, and the Joker succeeded in corrupting him, but they refused to allow the people of Gotham lose hope and believe that, so instead of a villan they portrayed him as a hero. I originally thought he was unconscious until reading up. I thoguht Batman's quote "Set the dogs on me" and how he'll be Gotham's hero at a time when they don't want him, the protector, the dark knight.