Some advice ---
The best thing you can do when you arrive is get yourself a cheap van as housing can be very expensive or unavalable in the mining areas, even the locals in the Pilbara reigon cant afford rent as the demand for employees housing has outstripped supply.
We have a lot of seasonal work in the agricultural reigons picking fruit or vegetables that seems to attract the backpacker types that can be quite hard and low paid, but a lot of folks, locals included follow the harvest trail and enjoy the itinerant lifestyle.
You will probably find your Irish accent would be greatly appreciated for call center work if you can handle that line of work.
A heavy truck licence can open a lot of doors for you as well as any skills in construction or welding.
Good luck mrduke!
linky ---
http://jobsearch.gov.au/harvesttrail/default.aspx