Displaying youtube videos:

In order to display a youtube video you should use the following url formula:
http://www.youtube.com/embed/video_id

For example the demo url is:
http://www.youtube.com/embed/A52_cHVg0tA

So how do you find your video_id?

The video id is in the url of the youtube video. Here are several different examples that will hopefully help you in finding this. As you can see the video_id is in bold.

http://www.youtube.com/dwayneparton#p/u/5/A52_cHVg0tA
http://www.youtube.com/watch?v=A52_cHVg0tA
http://youtu.be/A52_cHVg0tA
http://www.youtube.com/v/A52_cHVg0tA?fs=1&hl=en_US