In iPhone Application, you can use the UIAlertView to create a message box. The following code is an example.

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Title" message:@"Your Messaage" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles: nil];
[alert show];
[alert release];

 


                                        
Done =)

Reference: simple message box popup?