<?php

        // Sort categories
        $root = Mage::getModel('catalog/category')->load(Mage::app()->getStore()->getRootCategoryId());
        $this->_sortChildren($root);
    }

    private function _sortChildren($parent)
    {
        Mage::log('Sorting '.$parent->getName(), null, 'acumen.log');

        if ($parent->hasChildren()) {

            $children = Mage::getModel('catalog/category')->getCollection()
                ->addFieldToFilter('entity_id', array('in'=>$parent->getChildrenCategories()))
                ->addAttributeToSort('acumen_category_sequence_number', 'ASC')
                ->load();

            // Sort children
            foreach ($children as $child) {
                if(isset($previousId)) $child->move($parent->getId(), $previousId);
                $previousId = $child->getId();
            }

            // Recurse
            foreach ($children as $child) {
                $this->_sortChildren($child);
            }
        }
    }

?>