Where do I find volunteer opportunities working with animals overseas that won't cost me anything?

I don't mind working with domestic animals or zoo/sanctuary animals or animals in the wild. I am experienced working with animals. I am happy to pay for flights and my own food but don't want to pay any "extras". I'm not afraid of hard work and am looking to volunteer between 3 and 6 months. I live in Australia and don't really mind where I go. Anyone got any tips? I've done a bit of searching on the internet but most agencies want to charge you a big fee for volunteering...

international volunteer program