How to save User preferences in iPhone app
Saving user preferences in iPhone app is fairly easy. It work as key/value pairs in NSUserDefaults object.
To save whether user prefers sounds on or off in your application you can do it as the following code block.
[[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"soundsOn"];
And to retrieve the sounds preferences value;
BOOL soundsOn = [[NSUserDefaults standardUserDefaults] boolForKey:@"soundsOn"];