South East Water in Victoria has a new for old replacement policy on shower heads.  Take your old water wasting showerhead along to a South East Water office and they'll swap it for a new water saving shower head.  See the South East Water website for details.

Another great little Aussie invention; this little device can be fitted to your water cistern to prevent it from continually flushing and wasting water. The FixaFlush adapter can be fitted to most toilets and doesn't require a plumber for instillation. Basically the device only allows the valve to lift and stay lifted while your finger is on the flush control button, thus preventing you cistern from getting stuck and continually running.
Check out the FixaFlush website for details.

According to their website, The Quench shower system can save you massive amounts of water at home by recycling your shower water while you shower.  You can have nice long hot showers without the guilt and only use 4 litres of water. Visit the Quench website for details.

Aerator taps add air to the water coming from taps to reduce water use, while still giving a full-bodied flow. They are inexpensive, easy to install (no plumber needed) and help save water in the kitchen and bathroom.

Available at all good hardware stores.