Brakerider:
I can't tell you much about the current process as I've been here a while but if you want Sydney or Melbourne then there's probably not much of a wait. More and more pilots are getting out of these bigger bases as their seniority affords it because of the cost of living.
A guy I flew with the other day has been here six months and bid for Sydney some weeks ago and was allocated Sydney in the very next roster. Outport base wait times though are much less predictable.