I was checking validation on my pages and found the only XHTML errors were from the suggested YouTube embedding code. A quick search revealed several XHTML valid code examples, and here is what I am using to center the frame under XHTML 1.0 Transitional (this fails 1.0 Strict validation – to make this validate under Strict, just remove align=”center”..):
<p align="center">
<object type="application/x-shockwave-flash" style="width:425px; height:350px;" data="http://www.youtube.com/v/sdUUx5FdySs">
<param name="movie" value="http://www.youtube.com/v/sdUUx5FdySs" />
</object>
</p>
Update:
I am now using div’s to solve page formatting issues..:
<div>
<object type="application/x-shockwave-flash" style="width:425px; height:350px;" data="http://www.youtube.com/v/sdUUx5FdySs">
<param name="movie" value="http://www.youtube.com/v/sdUUx5FdySs" />
</object>
</div>