Australian SIMs

On the basis that all knowledge is contained in fandom, does anyone know of a source for Australian PAYG SIMs with reasonable data rates? I'm looking for something like the Three PAYG deal in the UK, where each £5 topup gets you 150MB of data as well as £5 worth of calls and texts, but the key requirement is 100MB or more of data for less than AU$30. Bonus points if Micro SIMs are available so that I don't have to cut down a regular SIM for use in an iPhone 4. And, of course, non-Australians have to be able to get them.