Use this code in the long description:
<object height="385" width="640"><param
name="movie"
value="http://www.youtube.com/v/XXXXXXXXXXX?fs=1&hl=en_US"><param
name="allowFullScreen" value="true"><param
name="allowscriptaccess" value="always">
<embed src="http://www.youtube.com/v/XXXXXXXXXXX?fs=1&hl=en_US"
type="application/x-shockwave-flash" allowscriptaccess="always"
allowfullscreen="true" height="385" width="640"></object></p>
The Bold X's indicate where you need to put the 11 digit code from the Youtube Video's URL