Hi there just to give you an update on the GST claim things. My friend successfully claim it with the receipt bearing its name. If you are a visitor, you can choose to get it refunded through your credit card or you can opt to transfer it to your Australian bank acc.

Sure can claim lol.
Make sure to remind her to bring the item with her (handbag or hand luggage). They need to inspect the item first.(they dont open it tho)

Im pretty sure you got a message from Optus saying that your phone is unlocked. If not, wait for 5 days and try to restore your iphone and put another simcard and see whether it is working or not. 10 days is basically the approximate time. Some people reported that their iPhone is unlocked as earliest as 2 hrs (emergency request such as travelling oversea etc) up to 7 days.

Like hihihehe said, anywhere is the same but you might want to go to this link first a day before purchasing;
http://www.apple.com/au/retail/iphone/availability.html

just to ensure your model is in stock