This is the huntsman spider, a common friend to be found in houses and garden across Australia. He's harmless really, don't let his large size intimidate you. Huntsmen won't bite humans unless provoked, are not venomous and are actually handy to have around the place, he'll use his speed and agility to keep your cockroach population under control.
Think of the huntsman as a handy pet. Respect his space, let him do his job and he'll look after you well.