With iOS8, you can finally link user to Settings app via openURL. For example, you can create a UIAlertView with a single button that takes user to the Settings app:
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:ICLocalizedString(@"LocationServicesPermissionTitle")
message:ICLocalizedString(@"LocationPermissionGeoFenceMessage")
delegate:self
cancelButtonTitle:@"Settings"
otherButtonTitles:nil];
[alert show];
In your UIAlertView delegate:
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
[alertView dismissWithClickedButtonIndex:buttonIndex animated:YES];
[[UIApplication sharedApplication] openURL: [NSURL URLWithString: UIApplicationOpenSettingsURLString]];
}