What kind of accommodation are you thinking about/looking for?
For the university colleges - I think applications close generally around september, its probably good to start putting in applications for interviews now etc - look to individual websites for particular dates/forms. Most the colleges have individual application forms, each with their own fees.
I'm not sure about university village - on their website they are accepting applications for semester 2, so I'm not sure whether they are yet accepting applications for next year. You could always give them a call.
If you are just looking at renting a place in the area then you wouldn't start looking until much closer to the time.
As to what is the best, that depends on what you are looking for. Do you want co-ed accommodation? (Anything bar Pauls or Women's college) Do you want meals provided? (If yes, any of the colleges) What is your budget? (colleges tend to be more expensive) Do you want something that is full of students or perhaps look just for private accommodation around the area? Do you care about the extra co-curricular activities/academic support the colleges can provide?
edit: also, Johns college made front page of the Sydney Morning Herald today if you want to check it out...