(as of this writing, the latest release is 3.3.0)
<script src="http://yui.yahooapis.com/3.3.0/build/yui/yui-min.js"></script>
<script>
YUI({
gallery: 'gallery-2011.04.20-13-04' // Last Gallery Build of this module.
}).use('gallery-yui-slideshow', function(Y) {
// Your code here.
});
</script>
var slideshow = new Y.Slideshow({ srcNode: '#someID' });
Example: