A WordPress child theme is a theme that inherits the functionality of another theme, called the parent theme, and allows you to modify, or add to, the functionality of that parent theme.
Read More @ http://designfestival.com/build-child-themes-in-wordpress-with-css/. This article shows how to create a basic child theme and explains what you can do with it.
For more reference : http://codex.wordpress.org/Child_Themes
You can see the example @ http://192.168.1.200/Temp/Jincy/wordpress/child-page/
Admin Url : http://192.168.1.200/Temp/Jincy/wordpress/wp-admin
Username : admin
Password : 142536