Follow the link and answer the quick question. then they will you send you the free ID tag for your pet. Then register your details and they will you send you the free tag.
This freebies is thanks to Lost Animal Homes Australia
(AUSTRALIAN RESIDENTS ONLY!)
http://www.ozbargain.com.au/node/1554
http://www.ozbargain.com.au/node/6039
but that was posted ages ago so..