Since I've been lazing around at home pregnant the last few months, doing not much besides eat and expand (it takes work to gain 20 extra kilos, and its not all baby!), I thought I'd try out the classic "you too can earn several squillion dollars a month from home" that seems to crop up all the time on the Internet, and usually aimed at stay-at-home mums.
The bottom line of course, is you can't earn very much at all, especially if you are outside of the US. Australians are a little under-represented in the "earning money from home" stakes, but a few sites came up that are either international or specifically Australian. Most take people from the UK, New Zealand and Australia.
A little research on taking online surveys and getting paid to read email will tell you that you have to sign up to every online survey site on the planet and spend your entire waking time filling out surveys (which might get you a few hundred dollars a month at best), something that is impossible for Australians as there just aren't that many sites. You also need to be in their target demographic for particular surveys, which usually means you need to be a particular age, income and location. This can be very limiting for someone in a rural or remote location - the places stay-at-home-mums really need that extra money.
Be careful with looking for this kind of thing though. Many sites that claim to be paid survey sites actually just refer you to other sites - or worse, charge you for a list of sites - without actually having any content of their own.