Use a simple <iframe> directive:
<iframe width="560" height="315" src="http://www.youtube.com/embed/oHAjPO-5vbM" frameborder="0" allowfullscreen></iframe>
Make sure that you have the "embed" link from youtube, not the url of the webpage. You can see the video playing at http://www.eurotans.com (scroll down the screen)
Maybe you can help me with my problem. I have a different video that I'm hosting on my site server. I can't get it to work on firefox, but it works on chrome, IE9, android and Iphone. Can you help me with this?