I interviewed with them in Calgary in August 2007, and I received a spot to commenced at Flinders in Feb of 2008. I am originally from Edmonton.
This year for international students I believe there are 20. 14 of those international students are Canadians, with 2 Americans, 2 from Singapore, 1 from India and 1 from Brazil.
Chances are you'll start off the interview doing a mini-case of some sort which isn't directly pertaining to medicine or science. For example, in my interview I had a mini-case where a woman owns a truck stop in Northern SA, and her core business is generated from truckies shipping cows and pigs. She goes away on a vacation for a week and comes back to notice her fuel sales are lower than she anticipated. You'll have a whiteboard, and you have to use your whiteboard to hypothesize why. Then, the interviews will give you a piece of paper with new information, and you have to show them how this new information changes your hypothesis.
After that mini-case they got right into questions, and the first question they asked me is "Why do you want to be a doctor?". The next question was "Why Australia? Why Flinders?". For the rest of the interview you'll get little scenarios that are used to gauge your empathy skills, and understanding of group dynamics (in addition to questions about yourself).
Also make sure you read up on PBL, they will probably ask you what you know about it.
Tony Edwards is the Flinders administrator who did the international interviews when I interviewed, and he's a really nice guy. For everyone who is going to interview, don't stress out. The more you relax, the easier it will be.
Good luck!