We are plnning a 6 week trip to Australia and are wondering if there is a multi-city air travel deal within Australia other than one connected to your ticket to get there.

There's http://www.rex.com.au/Backpacker/default.aspx and though it is marketed at backpackers, any visiting traveller or one who happens to have a nonAustralian passport can use it.

And then all you can do is attempt to seek deals on offer, www.webjet.com.au showing all fares on offer at any given time and www.virginblue.com.au have what they call lunch time deals you'll see on their site between 12 and 1 daily.

Given economic downturn, there have been plenty of airfare sales on at moment but they do take some planning ahead.

It's best to keep an eye on all the main domestic carriers: www.qantas.com, www.jetstar.com.au. www.virginblue.com.au and www.tigerairways.com.au (Tiger so far offering limuited routes ex Melbourne and Adelaide). You should be able to sign up for email alerts of upcoming sales. The specials offered can be extremely attractive, but as Bushranger notes it will take some planning to take advantage of them.

I was told about http://www.virginblueairpass.com/
Supposedly it will be cheaper if you use webjet, but for my case it isn't, as long as I can find a use for the third leg.
Yeah, you have to book at least three one-ways and you must have a non-australian passport.

Looks to be good value pi and I haven't even noticed them marketing it, maybe a recent creation.

I'd book direct with Virgin and though you can book airfares direct with webjet, maybe pass too, they do charge a booking fee and so whilst it is a good site to find cheapest fares, when that is done, it'll still be better to book direct with the airline.

We recently returned from Australia and had purchased the Virgin Blue Airpass from Canada. The concept was good but it was not quite as flexible as I had hoped. Three of my four flights had time changes and one proved to be impossible for further arrangements ie car rental and prepaid hotel. Their response was I could just cancel and put a credit on my account. That was not acceptable when you are overseas.

The baggage allowance was 1/2 the overseas allowance so we paid $70 overweight. (So be careful!). Also the carry on limit was 7 kg. I was aware of the difference but could 'shed' nothing else. Good news was they used cumulative weight of your group. Also while they say you can make changes up to 24 hrs ahead, I could not change the flight distance even while I was still out of the country. Because of that there was one flight we never used. If you use their customer service by phone you pay extra for that service. So in the end it created more pressure and hassle than it was worth.

Best advice would be to try and use the same overseas carrier and domestic if they had a more liberal baggage policy for overseas travellers. We used Air New Zealand and thus our problem.