Since the FDA regulates what is manufactured in the US, it may have an effect of what products are available in Australia....
Now onto your question. The ephedra free variety will not help you lose that much weight. However, I do feel that these 'fat-burners' provide me with the energy to run longer and harder when doing my morning cardio sessions because the caffeine in them wires me pretty good. It also helps with the intensity of my lifts - a little. So on my cardio days, i take it. One can argue that it has an indirect effect by allowing you to go more balls out, helping you burn more calories, and therefore have a metabolic and energy raising effect for the day. But it's not coming from the product per se, but resulting from your stimulated workout session.
Let's put it this way - if you didn't change your diet or training habits and took the stuff, you wouldn't look any different - so don't expect it.
If you want to feel wired and run harder when you do your cardio, then I think it's worth it. Then again, you can always drink a couple cups of coffee beforehand. I would rather not have to piss in the middle of my cardio session and I'm WAY too lazy to turn on a coffee maker in the morning.