How to create a child theme of an existing theme

Let's make a child theme of twentyten theme.The following steps are to be followed.........

1.Create a new folder under wp-content folder(where all other theme exist) and name it.Suppose we named it ChildofTT
2.Open any text editor(dreamweaver,notepad) and create a style.css file and save it in ChildofTT folder.
3.Add these code to style.css file

@import url('../twentyten/style.css');

/*

 Theme Name : Child of Twenty Ten
Theme URI : www.yoursite.com

Description : This is your first child theme
Author : Your name
Template : twentyten

*/

4.Go to your Dashboard->Appearance->Themes and you will find a child theme of Twenty Ten theme