Plugin Name: Main categories
Plugin URI: http://rudd-o.com/projects/wp-main-cats/
Description: Provides a template function to display main categories and a management interface for them
Author: Manuel Amador (Rudd-O)
Author URI: http://rudd-o.com/

With this plugin, you can display selected "main" categories on your blog's sidebar or top navigation bar.  Akin to wp_list_cats(), the provided function wp_list_main_cats() accepts the same arguments, but filters out all categories not deemed "main".  You choose main categories via the WordPress category management administration panel.

Another function called wp_list_secondary_cats() allows for the listing of any secondary (non-main) categories in your blog.

To use:
- deploy into its own wp-plugins/wp-list-main-cats/ directory (basically, preserve the package's directory structure)
- activate through the plugin manager
- access the Manage panel in the WordPress administrative interface
- go to Categories
- select your main categories
- add the wp_list_main_cats() tag (perhaps in replacement to the wp_list_cats()) on your template