Qualifications
As of 2012, in order to be a certified audiologist, you've got to have a doctorate degree. Your mother will be so proud of you, the doctor in the family.
Many audiologists earn an AuD degree (Doctor of Audiology). You can also go the route of other doctorate degrees such as PhD (Doctor of Philosophy) and ScD (Doctor of Science), but only from accredited universities that specialize in this sort of thing.
Of course, all of the above means that you already earned a bachelor's degree in communication sciences and disorders or a related discipline. You're going to be in school for a while before you're ready to even think about getting one o' them extra-fancy degrees. Check out the Speech-Language-Hearing Association; itoffers a vast amount of information regarding academic programs and certification processes (source).
Of course, getting a doctorate degree is no easy (or cheap) endeavor. You've got to have a deep, deep interest in science, a desire to help people, and, of course, you've got to start out—and remain—committed. Becoming a doctor takes a long time... and so does paying off the loans.