So anyone downloaded this game yet? I plan to download it when I get home tonight… can anyone please explain to me how this works?

I didn't pre-order the game but it's 28th here in Australia and I'm assuming it will be 28th in America as well by the time I get home this evening after work. Can I start downloading the game tonight even if I didn't pre-order? How long did it take you folks to download this? Any Australians purchased this game? Is it $20 AUD as well?