Back on December 22, I flagged an offer for free Gold status with Hilton HHonors through May 2013.
That offer, believe it or not, appears to still be alive.
As of 10 Mar 2012, still worked for me! Thanks!!! As Tamas said, register or change your Hhonors account to Australia, use the code above, then once you get the congrats screen simply change back to your real country.
The ‘code above’ refers to 442394 or 411945.
Gold status, of course, gets some modest upgrades, continental breakfast, free internet, and discounted multi-night redemption stays.