It's a touristy country, and there are LOTS of companies organising tours. Here are just a few

(from http://www.exploroz.com/4wdsearch/Categories/Tours.asp):

Great Divide Tours 

Regions: Sydney/Blue Mtns, Snowy Mountains, Tasmania, SA Deserts,

Red Centre, East Victoria, Kimberley, Far North Qld, Outback Qld,

Top End, Outback NSW, Western Deserts

Misty Mountains 4wd Tours & Tag-a-longs 

Regions: Sydney/Blue Mtns

Cape York Connections 

Regions: Far North Queensland

Bob-A-Long Bush Tours 

Regions: Kimberley, Pilbara, WA Coast, WA South Coast,

Western Deserts

Skytrek Willow Springs Station Pty Ltd. 

Regions: Flinders Ranges

Global Gypsies Pty Ltd 

Regions: WA Coast

Direct Four WD Awareness 

Regions: SA Deserts

Remote Area Tours 

Regions: Western Deserts

Murchison Safaris 

Regions: Pilbara, Western Deserts

Gibb River Road Bus Services 

Regions: Kimberly

Barking Gecko - MTB Tours 

Regions: Flinders Ranges 

If you have a little group wanting to go to Aus, we can help to put together a package, plan a route, make bookings, and provide local knowledge.