There are a couple of different ways that you can post Youtube videos. They all have the same end result.
The first is by using the URL of the video. For example:
Code:
[youtube]http://www.youtube.com/watch?v=HtvIYRrgZ04[/youtube]
will produce:
You can also, but it isn't necessary, just use the video ID:
Code:
[youtube]HtvIYRrgZ04[/youtube]
A second, and newly introduced way, is to display the videos in widescreen high definition. You can use the same methods as before, but the tags are different:
Code:
[hdyt]HtvIYRrgZ04[/hdyt]
I highly recommend using the new HD format.