The plugin based on the functionality of pericat's plugin, but uses a GUI instead of a textual specification language for the category ordering, indentation, and spacing. Because the code is radically different, pericat suggested that I release it as a separate plugin.
This plugin allows the blog administrator to set an explicit ordering, spacing, and indentation of categories in the category list that appears in the sidebar. The administrator specifies the ordering in the new "Category Order" management page. There is also an option for placing the category post count inside the link.
The plugin overrides any ordering or indentation of categories created by the list_cats() WordPress function. It works by dissecting the normal ul or br formatted list that WordPress creates, then reconstructing a custom ul or br formatted list based on the new custom ordering and indentation. Since the plugin modifies the display only, you can revert to the default ordering by simply disabling the plugin.
The plugin handles subcategories (by overriding the parent-child relationship), and the post count on categories. If the plugin fails for you, it is likely that your category list HTML is somewhat different than what the plugin expects. In this case, please email the HTML snippet to the me and I'll try to fix it.