WordPress.org

To install the plugin just follow these simple steps:

1. Download the plugin and expand it.
2. Copy the 'order-categories.php' file into your plugins folder (wp-content/plugins/).
3. Login into the WordPress administration area and go to the Plugins page.
4. Locate the Order Categories plugin and click on the activate link
5. That's it, now you can go to Manage > Order Categories and reorder the categories the way you want.
6. If you use wp_list_categories(), make sure you don't specify an order (e.g. wp_list_categories('orderby=count');).