I just posted this on the Whirlpool forums, posting here for those interested too:
They are now selling the iPhone 4 outright in the US. This means you can get them cheaper than Australian RRP if you have a means to get products delivered to Australia from the US, eg
http://www.priceusa.com.au
http://www.shipitto.com
Outright prices on the US Apple Store are:
16gb iPhone 4 – $649 US
32gb iPhone 4 – $749 US
Which works out to be roughly $609 and $703 respectively (at the exchange rate right now).
If you then add say $50 for delivery, that's $659 and $753 for the iPhone instead of the $859/$999 if you got it locally. You may need to add sales tax if the mail forwarder you use isn't in a state where there is no sales tax – priceusa is in oregon so you don't have to pay sales tax if you get it from them.
Just a heads up for those interested in buying the phone outright rather than going on a plan.
Personally, I much prefer going on a plan as it works out to be a better deal in the end, however being able to save $200 on the outright price is pretty impressive!
I'm not sure what the AppleCare/Warranty implications are if you import for the US, but I believe AppleCare is valid worldwide? I'm also not aware of any issues you may have using an Australian SIM in an American Phone, but you may want to check that.
1) No local (Australian) warranty.
2) No local (Australian) Out of Warranty support.
3) No A-Tick (required).
4) No local (Australian) AC charger included.
5) No C-Tick/A-Tick on the USDA AC Charger.
Of course, they are cheaper here on a plan - also prices have dropped. eBay sellers and even some dealers are offering similar prices here in Australia. I got a 32GB iP4 in White for $19 a month ($456) minus a $87 credit ($369) on my $29 cap plan.