$55 Ultimate plan from Telstra is the way to go. There's not much info on their website about it for the iphone, but you can do it. You will have to pay $150 on your first bill for the base model. $150 not much for what you get! Includes 150 mb, which i've never come close to. I do have wireless at home, and work though. NextG does kick A. I use my phone a fair bit as i don't have a landline, and i've never busted my 150 mins.
BOM! My favorite app! With NextG i get coverage across most of the top end. Pretty handy having weather radar in your pocket on those long legs in the wet. Although it has been pretty weak lately.
Seriously look into the Ultimate $55 it's worked for me. I was soooo freakin close to switching to Optus, cause how can you beat their plans? If you need it for work though there is unfortunately only one option.
Cheers,
Greaser...Iphone lover...