This is just a short reminder for me and a note for you on how to write a valid XHTML strict snippet to insert a YouTube video.
<p>
<object id="video_o" type="application/x-shockwave-flash" data="http://www.youtube.com/v/JaJbDln7oGA" width="560" height="340">
<param id="video_p" name="movie" value="http://www.youtube.com/v/JaJbDln7oGA" /><img src="http://www.youtube.com/v/JaJbDln7oGA" width="560" height="340" alt="titolo_video" />
</object>
</p>