There are many places that will help you adjust the embed information from YouTube – however, if your site is XHTML Strict (like this one is) you will still not validate.
In swings Tools4Noobs to the rescue! They have many great resources in the Online Tools section.
I went through five or six different sites that altered the embed code before I found this. This was a VERY GOOD thing! I was pulling my hair out trying to make this work on my own.
