XHTML Embed
Googling for an XHTML 1.0 Strict compliant way to post a YouTube video to my blog, I found my answer.
If you use Textpander (as I do) you can create a shortcut (I use <you) to call the following macro:
<object type="application/x-shockwave-flash" width="425" height="350" data="http://www.youtube.com/v/%|"><param name="movie" value="http://www.youtube.com/v/" /></object>
