I'll be arriving in Australia (Melbourne) on 18 March 2015. I'll need to buy a car very soon after I arrive and I'll need to get car insurance. I have a full Irish driving license and 7 year's experience. What else do I need to get insurance?
There are two flavours of car insurance in Victoria:
Compulsory Third Party (CTP) insurance is mandatory and included with your car registration ("rego"). Prices are fixed, around $750/year all in at time of writing, and everything is handled by VicRoads, the state road agency. If you purchase a used car, it may include some months of prepaid rego and this may affect the purchase price; you'll still have to pay to get the rego transferred to you.
"Car insurance" means anything beyond this: third party property (damage to other people's cars), third party fire & theft, and comprehensive (covers your own car as well). This is optional but recommended, although people driving old clunkers often don't bother. Try Compare the Market to see prices. Note that, as a rule, only experience driving in Australia counts, so you'll be paying full premiums to start off with.