If your youtube url looks like this: http://www.youtube.com/watch?v=U0kJHQpvgB8 you need this part: U0kJHQpvgB8 and surround it with [YOUTUBE] tags PHP: [YOUTUBE]U0kJHQpvgB8[/YOUTUBE] result: [YOUTUBE]U0kJHQpvgB8[/YOUTUBE]
It actually works either way at EC (at some sites it doesn't ) - you can also put the whole http://www.youtube.com/watch?v=U0kJHQpvgB8 inside the YouTube tags too: result: [YOUTUBE]http://www.youtube.com/watch?v=U0kJHQpvgB8[/YOUTUBE]