www.musolist.com is a good resource for contacting musicians. Local papers often have a musical section with wanted ads too.
Local music magazines and papers often run muso wanted ads too, one example in Perth is the XPress magazine.
As previously mentioned bulletin boards in music stores often have muso wanted ads, or check the store windows or even just ask the guys behind the counter (on a quiet day obviously).
You could also check out any local universities or colleges that offer music related courses and ask the department head if there is a message board and even mention you are looking for band members, he may know some students or ex students in bands, or at least some lesser known resources around town, even maybe a hint which pubs music students hang in can be useful.
When you go to check live bands out, get there early or stay late and without getting in the way too much see if you can ask them about local opportunities and where to find them. You may need to haul some gear for them tho hahaha, and this method is also useful for gleaning inside information you might not otherwise find out about, like venues or agents to avoid etc etc.
If all that fails then there's always placing your own ads for muso's in the same places listed above, or anywhere you think a suitable muso might see your ad
Good luck finding some people.
