If you need to run akismet on a big queue, you can do it with this code and run it from the command line. Drop it at the root of your wordpress install (where is wp-config) and run it with the command line php.
<?php
require_once dirname(__FILE__) . “/wp-load.php”;
if(!function_exists(‘get_plugins’)) {
require_once ( ABSPATH . ‘wp-admin/includes/plugin.php’);
}
require ABSPATH . ‘wp-content/plugins/akismet/class.akismet-admin.php’;
$_GET[‘recheckqueue’]=true;
$_REQUEST[‘action’]=’akismet_recheck_queue’;
$zz=new Akismet_Admin();
$zz->recheck_queue();
?>
(Edit: this shouldn’t be needed in newer versions of Akismet as you can do it from the panel).