To study at the Sydney English Academy you will need to apply for a Student, Tourist or Working Holiday visa. A Student visa will allow you to study for 2 to 50 weeks full time. A Tourist visa will allow you up to 12 weeks of study, and a Working Holiday visa 17 weeks of study.
Full information can be found on the official Australian government website, www.immi.gov.au/. There is also information on the Study in Australia website at www.studyinaustralia.gov.au.