well. how do u mean??
is it one spider or several hundred. basement or attic?
and are you asking just how to get rid of them or how to kill them.
shit, Australia sure got the long end of the stick when it comes to leathaly poisonous critters.
ok well heres the list of prevenatives i use for spiders round here. (we have black widow's and brown recluses mostly)
boric acid powder, works on most insects, apply to baseboards, within the week all the spiders will have moved high enough to vacuum up.
Diatomaceous earth, in fine powder form spread through attic eaves and basement crawlspaces, also discourages many other insects
(also snakes rats and most things with scales or paws) you can use finely crushed lavarock to somewhat the same effect
find a natural deterant, look online for its natural enemies and predators, then pick one youd rather have than a redback.
i use cheap anole lizards from a petstore.
they also make some plug in sonic deterants that are said to chase bugs away, but u have to get enough to covor your whole house or the damn things just move
our local badboy the brown recluse
http://en.wikipedia.org/wiki/Brown_recluse has only one natural enemy, the black cave cricket, fortunatly we have those too
so its just a matter of colecting them
sooooooooooooo that covers most the non toxic aproaches, after that comes fire.