The ways to turn off the camera shutter sound on the iPhone are numerous. You can disable all the sounds by turning on silent mode, turn down the application volume, or change or delete the camera shutter sound file. Each method has drawbacks. Turning on silent mode disables all the sounds on the iPhone, and only lasts until you turn silent mode off. Turning down the application volume silences all the applications in the phone. Since the iPhone does not include a file manager program, renaming the file requires you to download application software to your iPhone, or to a computer.
Slide the silent mode switch to "On" before you take a picture. The switch will silence all the noises on the iPhone.
Open the camera and turn down the application mode volume. This setting controls the volume for all the phone applications.
Download a file manager for the iPhone and delete or rename the file photoShutter.caf. You can find the file in System > Library > Audio > UISounds.