I think that the standard:
<script type="text/javascript">
var _paq = _paq || [];
_paq.push(["setDocumentTitle", document.domain + "/" + document.title]);
_paq.push(["setDomains", ["*.my_domain.org"]]);
_paq.push(["trackPageView"]);
_paq.push(["enableLinkTracking"]);
(function() {
var u=(("https:" == document.location.protocol) ? "https" : "http") + "://stat.my_stat_domain.org/";
_paq.push(["setTrackerUrl", u+"piwik.php"]);
_paq.push(["setSiteId", "1"]);
var d=document, g=d.createElement("script"), s=d.getElementsByTagName("script")[0]; g.type="text/javascript";
g.defer=true; g.async=true; g.src=u+"piwik.js"; s.parentNode.insertBefore(g,s);
})();
</script>