I have a simple view controller (SecondViewController) used to manage a UITextview (I'm building a simple editor) this is the code of the SecondViewController.h

    @interface SecondViewController : UIViewController {
 IBOutlet UITextView *textView;
}
@property (nonatomic,retain) IBOutlet UITextView *textView;
@end

and this is the SecondViewController.m

//
//  EditorViewController.m
//  Editor
//
//  Created by elio d'antoni on 13/01/11.
//  Copyright 2011 none. All rights reserved.
//
@implementation SecondViewController
@synthesize textView;

/*
 // Implement loadView to create a view hierarchy programmatically, without using a nib.
 - (void)loadView {
 }
 */

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];
 self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"uiViewBg.png"]];
 textView.layer.borderWidth=1;
 textView.layer.cornerRadius=5;
 textView.layer.borderColor=[[UIColor darkGrayColor] CGColor];
 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillAppear:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillDisappear:) name:UIKeyboardWillHideNotification object:nil];

}

-(void) matchAnimationTo:(NSDictionary *) userInfo {
 NSLog(@"match animation method");
    [UIView setAnimationDuration:[[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue]];
    [UIView setAnimationCurve:[[userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] intValue]];
}

-(CGFloat) keyboardEndingFrameHeight:(NSDictionary *) userInfo {
 NSLog(@"keyboardEndingFrameHeight method");

CGRect keyboardEndingUncorrectedFrame = 


[[ userInfo objectForKey:UIKeyboardFrameEndUserInfoKey ] 
  CGRectValue];
    CGRect keyboardEndingFrame = 
 [self.view convertRect:keyboardEndingUncorrectedFrame 
                  fromView:nil];
    return keyboardEndingFrame.size.height;
}

-(CGRect) adjustFrameHeightBy:(CGFloat) change 
                 multipliedBy:(NSInteger) direction {
 NSLog(@"adjust method");

return CGRectMake(20, 
                  57, 
                  self.textView.frame.size.width, 
                  self.textView.frame.size.height + change * direction);


}
-(void)keyboardWillAppear:(NSNotification *)notification {
 NSLog(@"keyboard appear");
    [UIView beginAnimations:nil context:NULL];
    [self matchAnimationTo:[notification userInfo]];
    self.textView.frame = 
 [self adjustFrameHeightBy:[self keyboardEndingFrameHeight:
          [notification userInfo]] 
     multipliedBy:-1];
    [UIView commitAnimations];
}
-(void)keyboardWillDisappear:(NSNotification *) notification {
 NSLog(@"keyboard disappear");
    [UIView beginAnimations:nil context:NULL];
    [self matchAnimationTo:[notification userInfo]];
    self.textView.frame = 
 [self adjustFrameHeightBy:[self keyboardEndingFrameHeight:
          [notification userInfo]] 
     multipliedBy:1];
    [UIView commitAnimations];
}

// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    return YES;
}


(void)didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];

// Release any cached data, images, etc that aren't in use.
}
(void)viewDidUnload {
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
(void)dealloc {
[super dealloc];
}


@end

the problem is that if load the view controller from a tab bar controller the textView doesn't resize when the keyboard appear, but the SAME code works if loaded as a single view based app. I hope I was clear enough. I used the tabBar template provided by xcode no modifications.