Arriving
 
At the time of writing this, Perth still has no public transport link to the International, or Domestic, Airport.  (A rail link is planned for the future).

So, to get from the airport to your accommodation means you have to either hire a car - pretty necessary for any trip to Western Australia - or take a taxi or either the Perth City or Fremantle Shuttle Bus Service:

The Perth Airport City Shuttle
Tel: +61 8 9277 7958
(Stops are located near hotels, motels and hostels in Perth).

The Fremantle Airport Shuttle
Tel: +61 8 9335 1614
http://www.fremantleairportshuttle.com.au
http://www.perthairport.com/default.aspx?MenuID=19
For useful information on Western Australia visit the West Australian Tourist Board:
http://www.westernaustralia.com/en/Pages/Welcome_to_Western_Australia.aspx