Appe has started to sell iPhones unlocked and outright from their online store. Optus has also began to sell pre-paid iPhone 3G and 3GS online as well.
Prices for the iPhone 3G and 3GS are below:
iPhone 3G 8GB (Black): $719
iPhone 3GS 16GB (Black/White): $879
iPhone 3GS 32GB (Black/White): $1040