The code that can be sent by SMS that will be executed on the phone can contain about anything, according to Miller, like requesting GPS location or turn on the microphone, or even DDOS the website of the RIAA.
Miller has not released much details about this very funny security breach, probably because of a deal with Apple, whom are working to fix the leak. Preferably before the Black Hat conference at the end of this month, where Miller will be giving a presentation on this leak, explaining it in much more detail.
'SMS is a great vector to attack the iPhone,' according to Miller. You can send an SMS with code, and the iPhone will execute it without user interaction.