edit: sorry guys, the post is a month old; noticed 'June' too late 
From: http://www.iphoneunlockaustralia.com/news-for-aussies/exclusive-optus-to-sell-iphone-for-350.html
From: http://www.iphoneunlockaustralia.com/news-for-aussies/exclusive-optus-to-sell-iphone-for-350.html
We have received information from an Optus World employee [via e-mail] that the iPhone will be sold by Optus outright (without any contract) for $350. The tipster has not told us whether this is the 8GB or 16GB model, however, we believe it would not be a surprise if the 8GB sold for this price (looking at the current price differences between the iPod Touch in the US and over here).
In one month, we'll just know if this is all true. Thank you to the tipster.