Living in Australia RentACoder, GetAFreeLancer etc.. may not prove to be economically viable due to the exchange rate (and the subsequent cut the website / PayPal will take) + you still have to declare your earnings and pay tax.
That’s not to say you shouldn’t keep an eye on them sometimes you will see jobs which may suit, but it will generally only be pocket money for nasty work.
I recommend that you start by looking for contracting work. As for the finances, if you are not savvy with dealing with contracts, insurance, tax and your tax allowance (from being self employed) then use an “Umbrella Company”. There are firms out there who will set up a company for you tailored for what you wish to do (in this case contracting and freelance work).
I am from the UK; I used a company called Giant Strongbox to do this. They take care of the contract, insurence and the payroll by working out the tax owed and allowances due to expenses. You will remain technically self employed, but you will not have unlimited liability. Using the umbrella company is just a way of outsourcing all the business and pay role fuss. It cost my approx £14 per week (so worth it). They also offered me great advise, notifications of payments, a nice clean web portal to add expenses etc.
Finding something similar will allow you to focus on the work and not the business fuss. You can stop the payments to the umbrella company as soon as you contract ends, and restart the payments whenever new work comes in.
For the £14 I paid per week I gained full insurance for whatever work I did... which was especially important considering my first contract was with a large bank.
It is important to get your name out there, have a good web presence (blog / show your up to date and competent, create a professional website with profile etc.) as it will be all about selling yourself. Meet people and network at conferences and generally get your business / yourself out there in whatever way you can imagine.
Hope that’s enough to get you started.
(Note: I’ve been working as a contractor / consultant for the past year, I’m 22 years old, just graduated yet by following the advice above I have had 4 contracts in the last year and a bit and things are going smoothly)