I know there is the MPMusicPlayerController class in which I can set and change the volume of a media file – what is the class called that allows me to change the system volume? ringtones and alert sounds etc.
Nothing in the apple forums is a good help right now:-)
Cheers Jeff
http://developer.apple.com/library/ios/#documentation/mediaplayer/reference/MPVolumeView_Class/Reference/Reference.html
…is your friend. See also this question – iOS: Change Device Volume
I believe Brian is correct in his comment that there’s no way to programatically do it in the public API – the user must trigger the action, to stop apps from doing all sorts of naughty things.