In the NT and Qld:
NT:
Northern Air Charter - Piston singles/Multi
Air Ngukurr - Piston singles/Multi (maybe turbine)
Air Frontier - Singles/Multi
Chartair - Singles/ Multi
QLD:
Savannah Aviation - usual stuff
Air Mt Isa/Westwing Aviation - more experience necessary but could get lucky!
Miscellaneous stuff near Cairns. - Again usually IFR so more exp.
I think alot of operators like the 500-700hr min these days (instructing/meat bombing/private flying) but you at the end of the day its up to the chief pilot and can be waived for the 'right' person.
Generally the guys i met on the trek north had a trade that they could find work in while they waited for a flying gig, or had previous work experience and were quite well rounded. I got a job with low hours and no 200 series experience so if i could then you can too. Be positive and have a good attitude and it will all fit into place!
Sitting in the pool at the backpackers (with the backpackers )
and having a beer while watching the thunderstorms in the distance was one of the better times while on the job hunt.
As has been said before, we've all been there!
Good luck and pm if you would like further info.
cheers
-ItsNUTZ!
p.s If you do the drive up make sure you have a reliable, simple to work on car for the trek up north. i.e commodore/falcon and remember the jerry!