You can self sponsor with this https://www.border.gov.au/Trav/Visa-1/189- bit of mucking about to get but once you have it you can work for any company. Otherwise company will need a company to sponsor you on https://www.border.gov.au/Trav/Visa-1/457- which is not hard to get but does limit the companies you can work for as not all will know how to do it.