YouTube positioning is being weird.

Your object tag is broken. I see this in your page:

<object height="355" width="425"></object></p>
<param name="movie" value="http://www.youtube.com/v/a4UPjkaE5vM&amp;rel=1&amp;border=0"></param>
<param name="wmode" value="transparent"></param><embed src="http://www.youtube.com/v/a4UPjkaE5vM&amp;rel=1&amp;border=0" type="application/x-shockwave-flash" wmode="transparent" height="355" width="425"></embed>

That ain’t right. WordPress has an unfortunately tendency to break overly excessive HTML code in posts. It wants you to post text and images, not to try getting all clever on it.

So, for embedding YouTube videos in WordPress, I highly recommend this plugin:
http://www.robertbuzink.nl/journal/2006/11/23/youtube-brackets-wordpress-plugin/

All you then have to do to *correctly* post YouTube videos is add text like this to a post:
[youtube=http://youtube.com/watch?v=4yX1F_nTcfc]
Just use the link to the video, see?

Even better, YouTube’s own “post to your blog” features use exactly this format. So this plugin will enable you to post YouTube video to your blog FROM YouTube. Nifty.

In the future, try to find plugins to do extreme things like posting YouTube videos. These tend to work better than the ways that services like YouTube tell you to do.