Wed Aug 24, 2:29 AM ET SYDNEY (AFP) - Muslims who want to live under Islamic Sharia law have been told to get out of Australia. A day after a group of mainstream Muslim leaders pledged loyalty to Australia at a special meeting with Prime Minister John Howard, he and his ministers made it clear that extremists would face a crackdown. Treasurer Peter Costello, seen as heir apparent to Howard, hinted that some radical clerics could be asked to leave the country if they did not accept that Australia was a secular state and its laws were made by parliament....