hmmm ... you'll likely have to pay about $20 for postage.
Steam in Aus won't help either. They'll just do the same price as retail over here. Case in point check out DOW2: Retribution. Steam it's $60, everywhere else it's $30.
It's pretty ridiculous that we Aussies have to pay that much for a digital distribution. The old arguments of us being so remote just doesn't stack up and this just shows it's pure price gouging by the local distributors.
It doesn't really affect me as I get everything from overseas now but even if it's $20 postage I'd still pay that and get it from overseas and screw the local distributors just as they're blatantly screwing us.
EDIT: On topic, I don't see how they could make a PC game region specific other than restricting sales here. They can't account for them multitudes of different PC hardware that's out there. Sure it's easily locked on things that are built all to one standard, like consoles, tv's, but I don't see how they can lock my DVD drive bought from Hong Kong that's going to play on my made in China monitor. Someone with a bit more knowledge can probably better answer.