Licenses

You can use your overseas licence, as long as the information contained on it clearly indicates the types of vehicles you are licensed to drive in your home country. If your native language is English, then this will not be a problem (generally) as the information on the licence will contain all of the relevant information. Never the less it may be best to obtain an International Driving Permit which are available for a few Euro at AA Ireland.

For those from non-English speaking countries, it is probably best to obtain an International Driving Permit - this will be a translation of what is on the licence, so that Australian police will be able to look at the licence, look at the permit, and see what types of vehicles the person is allowed to drive.

In some states, those with overseas licences are subject to special blood alcohol limits - for example in NSW, this is 0.02 (compared to the normal limit of 0.05).

Those who obtain permanent residency can use their overseas licence for three months from the date of visa issue (may vary between states). After this they swap their licence for an Australian licence. As long their country is on a list.
See International drivers for more info

Renting

1. Avis
2. Budget
3. Delta
4. Hertz

Backpacking Rents

Really one of the best in Australia . Mention you found them here on www.IrishDownUnder.net - www.OzEire.com and purchase a car from them before your arrival and receive 2 nights Free Accommodation (dorm beds 2 persons) and Free Airport Transfer .