Apple promised every iPhone 4 customer a free case to deal with any potential reception issues, but as the Australian rollout this Friday draws closer, the mechanics of that process still aren't clear — unless you happen to be an Optus customer.
As I write this, Apple hasn't yet said whether it will follow the same model as it has in the US of getting users to download an app to order their free replacement. That would be consistent, but offering a free case at the point of purchase would arguably be simpler, since (unlike the US) the phone has only gone on sale after the arrangement was announced.
The one bit of concrete information right now is that Optus is offering a free case for anyone who buys an iPhone 4 through its stores or website. The fact that Optus is making a point of announcing that perhaps suggests that it won't otherwise be a standard inclusion but, as with so many iPhone-related details, it seems we won't know until close to launch.