Update 2:The Apple Store went down for a bit late Friday, and returned with iPhone 4S Pre-order pages. [Apple]
Update 1: I'm fresh off a phone call with Apple's PR reps, who stated that the on-sale time has to equate with midnight in California, which still equates to the 7th here as well; that should equal 6pm AEDST.
Earlier: Over at Lifehacker, Gus noted that despite the 7th date, he'd been told by Apple this equates to the 8th here, in accordance with that pesky international dateline. That tallies with the original local press release, which also mentions the 8th, although a commenter on the Lifehacker story notes that Apple's phone staff informed them it'd be today, once it slips over to the 7th in the United States. As such, it may be wise (if you're keen) to keep an eye on Apple's website around 4pm this afternoon. [Lifehacker Australia]