the source code has to be like this:
<object type="application/x-shockwave-flash" data="http://www.youtube.com/ v/ VideoID" width="480" height="360">
<param name="movie" value="http://www.youtube.com/ v/ VideoID" />
<param name="quality" value="high" />
<param name="allowFullScreen" value="true" />
<!-- Fallback content -->
<a href="http://www.youtube.com/ watch? v=VideoID">
<img src="http://img.youtube.com/ vi/ VideoID/0.jpg" width="480" height="360" alt="[Video title]" />
YouTube Video</a>
</object>
enjoy 🙂