150 points are given to the answer if each of these related questions:
1) I have an About form, I want to always appear in the center of the MDI parent form, and as long as it is visible, I want the other forms to not be clickable (Just like the way you can't focus to the main window of Word when you have a dialog box open.) Is this possible?
2) I have a menu item in the parent form, which calls Show() method of one of the child forms. I want to add a functionality, so that, when that menu item is clicked and the child form is minimized, it restores the child window.