For information on visa requirements, visit the US Embassy site via one of the following links:
Information on ESTA Visa Waiver Program – https://au.usembassy.gov/visas/visa-waiver-program/
Information on Non Immigrant visas – https://au.usembassy.gov/visas/nonimmigrant-visas/
Information on Media and Journalist Visas http://www.ustraveldocs.com/au/au-niv-typei.asp