How to open preferences/settings with iOS 5.1?

It is little tricky , i get by the removing the subviews in *TWTWeetComposeViewController*, so it shows only alert when user is not loged in and by the clicking on setting button , we can open Setting page in my app.

     + (void)setAlertForSettingPage :(id)delegate 
    {
     // Set up the built-in twitter composition view controller.
        TWTweetComposeViewController *tweetViewController = [[TWTweetComposeViewController alloc] init];


        // Create the completion handler block.
        [tweetViewController setCompletionHandler:^(TWTweetComposeViewControllerResult result) {
            [delegate dismissModalViewControllerAnimated:YES];
        }];

        // Present the tweet composition view controller modally.
        [delegate presentModalViewController:tweetViewController animated:YES];
        //tweetViewController.view.hidden = YES;
        for (UIView *view in tweetViewController.view.subviews){
            [view removeFromSuperview];
        }

     } 

here , delegate is your viewcontroller , if you are using this method inside your viewcontroller just use self instead of delegate.

EDIT: If you get any deprecated errors, use the following iOS6 compatible code instead:

- (void)setAlertForSettingPage
{
    // Set up the built-in twitter composition view controller.
    SLComposeViewController *tweetViewController = [SLComposeViewController composeViewControllerForServiceType:SLServiceTypeTwitter];

    // Present the tweet composition view controller modally.
    [self presentViewController:tweetViewController animated:YES completion:nil];
    for (UIView *view in tweetViewController.view.subviews){
        [view removeFromSuperview];
    }
}