Good question. Ideally, there would be a way of selecting a system sound using AudioServices. However, the following statement from Apple’s “System Sound Services Reference” suggests otherwise:
In Mac OS X, when a user has
configured System Preferences to flash
the screen for alerts, or if sound
cannot be rendered, calling this
function will result in the screen
flashing. In Mac OS X, pass the
constant
kSystemSoundID_UserPreferredAlert to
play the alert sound selected by the
user in System Preferences. In iOS
there is no preferred user alert
sound.
Since it seems like the SDK has little to offer, you might wish to mimick the system sounds by using your own wav file. There is a nice library at the following link, perhaps it will have the sound you’re looking for: http://sites.google.com/site/iphonesounds/iPhoneOriginalSystemSounds_WAV.zip
Good luck!