magento-meta-hreflang.php

foreach (Mage::app()->getWebsites() as $website) {
    foreach ($website->getGroups() as $group) {
        $stores = $group->getStores();
        foreach ($stores as $store) {
            echo '<link rel="alternate" href="' . $store->getCurrentUrl() . '" hreflang="' . $store->getConfig('general/locale/code') . '"/>' . "\n";
        }
    }
}