Go to the website Suzy, its a ballot, you register and they randomly choose people, like they did for the Olympics ceremonies.
Extract from
http://ten.com.au/oprah.htm webpage
Please note: Tickets won't be available until MID OCTOBER. We'll be launching a lottery process that will allow regististration anytime within a 48 hour period and after the registration closes, it's a random lottery selection. This is the fairest way to ensure all Oprah fans have the same chance to be a part of Oprah's Aussie Adventure! Interested in attending the live taping of "The Oprah Winfrey Show" in Australia?
Good Luck,
Cheers
Chris