<?php
/*
Plugin Name: Seo-Without-Category
Plugin URI: http://mywordpress.ru/rubriki/plaginyi/seo-without-category/
Description: This plugin remove word 'category' from your nice category-style permalinks. So, if you set permalinks as /%category%/%postname%/ or /%category%/%postname%.html, your links to categories are http://super.com/category/mycategory/. Now your category url become http://super.com/mycategory/.
Author: Sergei Volkov aka Volkman <serg@megalith.ru>
Contributor: Sergei Volkov aka Volkman <serg@megalith.ru>
Author URI: http://megalith.ru/
Version: 1.0
*/ 

function seo_wo_category_category_link($catlink1) {
        $catlink1 = str_replace('/category', '', $catlink1);
        return $catlink1;
}

function seo_wo_category_rewrite_rules_filter($catlinks) {
	return array_merge(array("(.+?)/page/([0-9]+)?/?$" => "index.php?category_name=\$matches[1]&paged=\$matches[2]"), $catlinks);
}

add_filter('category_link', 'seo_wo_category_category_link', 1, 1);
add_filter('rewrite_rules_array', 'seo_wo_category_rewrite_rules_filter', 1, 1);
?>