First Off, buy Camps Australia Wide and Caravan Parks Australia Wide, available from most camping stores and RAC and possibly NRMA.
The new edition of Camps Australia Wide (Camps 7) is due out around Feb/March 2013 although updates are available online for a couple of years, a new one needs to be updated anyway due to time lapse since publication and hitting the bookshelves. See this link;
My wife and I are about to head west from NSW central coast in two weeks. We drive a 3litre Holden Colorado turbo diesel and tow a Billabong 22ft (internal) van with an ATM of 2700kg.
We will be away only 6 weeks (work wont allow us more time and neither will the mortgage) and hope to provide some useful information regarding fuel prices (diesel) as we travel.
Like DUH has suggested Camps Australia is a fantastic guide for travelling this awesome country of ours.
We plan on free camping on the way over and back and staying at caravan parks that are dog friendly (we have a 4yr old maltese ****zu named Sam). We are travelling down the Hume then Sturt Hwys to South Australia then across the Nullarbor to Esperance then Albany, Margaret River, Perth, Kalgoorlie, then back home via Broken Hill.
The internet is a great source of information and it depends on how long you plan on going for, budgets, if you are taking animals, what interests you have, etc etc.