While the EDGE iPhone could only be used on Telstra (probably why Apple didnt bother bringing it here); the 3G version can work on 3, Optus and Vodafone as well. However CNET has recived news from an insider that Optus is the one most likely to get the iPhone. It would be by no means an exclusive deal like that of AT&T in the states.
The handset is also expected to be sold simultaneously by Apple outlets at the full retail price.
Both Optus and Apple have refused to comment on the story.