Vodafone have also been actively advertising a $39 5Gb wireless plan, don't know much else about it at this time.
Edit : so I did some searching, came up with this:
http://www.vodafone.com.au/Personal/...band/index.htm
"Vodafone Mobile Broadband operates on our 3G broadband network so you'll enjoy fast downloads within the 3G broadband areas, which cover metropolitan Sydney, Central Coast, Melbourne, Canberra, Brisbane, the Gold Coast and Sunshine Coast, Adelaide and Perth, plus all major international airports in Australia. When you venture outside 3G broadband areas, you'll be switched seamlessly onto our GPRS network and you'll only be charged one rate.
With 3G broadband technology you can now enjoy data download speeds typically ranging from 600kbps to 1.4Mbps (based on network testing). Keep in mind various factors such as coverage, your location, your hardware and software, the source of your download and general network and internet traffic will impact on actual speeds experienced."
"An amazing 5GB for only $39 a month, plus free USB modem or data card when you sign up with us on a 24-month contract. Buy direct or visit a Vodafone store today."