Can anyone tell me what the main bus operaters are in oz? or some handy website? Just cant seem to find them on the web
Cheerz
Greyhound is the only "main" (countrywide) bus company afaik (there also used to be McCafferty's, but they bought Greyhound, and now they're the same). There's also lots of smaller regional ones like Firefly (Adelaide to Sydney), but see your Lonely Planet for those, depending on where you'll be.
I caught Premiere Motor Service from Brisbane to Sydney. They had an unlimited stops ticket for about $100 (can't remember the exact price now) with the only condition that you didn't backtrack. They had coach services all the way from Cairns to Melbourne (via Brisbane and Sydney), so pretty much the whole east coast. An unlimited stops ticket from Cairns to Melbourne would cost more than the above price though.