This year the education department cracked down on out of zone enrolments ( previously it was up to individual schools). Apparently they are allowing sibling enrolments until 2015 in out of zone schools.
I have a friend who applied for out of zone, the education department said no. I applied to the same school the previous year and we were offered a place (also out of zone).
I don't think there is a map that is clear enough to understand! It's probably worth checking with each school if there is more than one in each suburb.
As far as I am aware public schools must take you in the catchment, obvious exception is the school is at capacity and there is another school nearby.