You can't compose a message in HTML, and use the "embed" code from the
YouTube video? That code looks like this from the YouTube site:
| <object width="425" height="355"><param name="movie" value="
"></param><param name="wmode" value="transparent"></param><embed src="
" type="application/x-shockwave-flash" wmode="transparent" width="425" height="355"></embed></object>
I would have thought that you could add it in an HTML composition window.
But I don't create HTML email, so I haven't actually tried it. I'd just link
it, myself.