This plugin allows for the creation and management of widget sidebars on a per-page basis from a single dynamic_sidebar() call in your theme sidebar.
To install, download the .zip, unpack it and upload to your WordPress installation in /wp-content/plugins/. Log in to the admin backend and activate it on the Plugins page. You should now see another menu item under "Appearance" called "Manage Sidebars" which will be where you can manage all of the sidebars.
In your theme, all you need to add is the following line where you would like the dynamic sidebar to show up:
<?php dynamic_sidebar( apply_filters( 'ups_sidebar', 'default-sidebar-id' ) ); ?>
In the above snippet of code, 'default-sidebar-id' is simply the ID for your default sidebar which you should define in your functions.php file using