Added since the conference
Here are some useful travel links to get you to Perth and then to the conference.
Virgin Blue and their 'Specials' page
Once you get to the airport you can use the Fremantle Airport Shuttle (about $35) or take a taxi from Perth Airport to Fremantle which will cost about $50.
Transperth looks after public transport in the Perth metro area (Perth to Fremantle is about a 30minute train ride)