goto ada.org..all info is there abt cbt.once u register for the exam(pay the fees)..they send u a letter with a number on it..jus call up and fix ur appt...u jus have to give 48 hrs notice to book ur exam and from the time u register, its valid for a year..so within a yr, anytime u can give the exam..
pros: flexibility and fast results
con: 100 $ more than pbt