Force the admin theme on additional non-admin paths in Drupal 6

gistfile1.aw

<?php

/**
 * In this example, it uses the administration theme on "node creation", "node edition",
 * "user registration", "user profile" and "forgot password" pages.
 */

function MODULENAME_init(){

	// The list of paths on which to use the administration theme
	$patterns = array(
		'user',
		'user/*',
		'user/password',
		'user/*/edit',
		'node/add/*',
		'node/*/edit',
		'node/*/delete'
	);

	$path = drupal_get_path_alias($_GET['q']);

	$use_admin_theme = false;
	foreach ($patterns as $pattern){
		if (drupal_match_path($path, $pattern)){
			$use_admin_theme = true;
			break;
		}
	}

	if ($use_admin_theme){
		global $custom_theme;
		$custom_theme = variable_get('admin_theme', '0');
		drupal_add_css(drupal_get_path('module', 'system') .'/admin.css', 'module');	
	}
}

?>