The NBN Co is the organisation established in 2009 by the Department of Broadband, Communications and the Digital Economy (DBCDE). The NBN Co has the massive task of rolling out the NBN network across Australia. The installation of the NBN across the whole of Australia is expected to take about 10 years.
However, the NBN Co is not Retail Service Provider (RSP) and you cannot get NBN services directly from them. Instead, you will need to choose a NBN retail provider (such as MyNetFone) in order to have your NBN internet and phone service operating. The NBN Co's job is to do the background work for the NBN and set up the infrastructure which allows everyone access to high speed internet.