Hi Mike
I've now spoken with my sister. She lives in Jandakot which is near Ali. It is SE of Fremantle and about 20 minutes from Kings Park. Elaine said that her son Peter plays soccer with Beeliar Soccer Club, Fremantle United and Fremantle Spirit.
Aparently soccer/foorball work a bit differently in Oz than in the UK. Australian Foorball is quite a rough game apparently involving a better than average chance of being injured, Elaine says - sounds like that Amercan game where they all wear crash helmets with wire stuff to protect their faces.
Soccer, apparently, is much less rough. Elaine pointed out that which of the clubs you could coach for depends on which part of Perth you choose to settle in, but she says the clubs have adult teams and kids' teams and that the ones Peter goes to are continually moaning that there are not enough coaches to meet the demand. She says soccer is the fastest growing sport in Australia.
Here are some links which might help your search:
Football Clubs + Perth - Google Search
Soccer Clubs + Perth - Google Search
The trick is to tell Google to look for Google Australia and then tell that to search for pages from Australia.
I'm getting a bit confused with it myself because I don't know which of the two Australian games you would be interested in helping with,
Cheers
Gill