Apple - Stop iTunes from opening when a device is plugged in?
Under System Preferences → Users → [you] → Login Items → select iTunesHelper, then click the minus sign and log out/into your Mac.
No devices will cause iTunes to launch (that's the whole purpose of iTunesHelper).
In iTunes there is an option to prevent the app to launch when a device is connected to your computer.
Open iTunes > Clic on a device in the sidebar > Scroll down to the "Options" section.
Then you have to make sure this little checkbox is un-check:
(source: f.cl.ly)
If the problem still occurs after that, come back here !
Open iTunes -> Preferences -> Devices
.
Make sure Prevent iPods, iPhones, and iPads from syncing automatically
option is checked.