Heya.
Some people aren't familiar with embedding youtube clips in the Forums, so here's a little help:
The link you copy from youtube will paste as something like this:
http://www.youtube.com/watch?v=MMLXoobDKWs

You only need the alphanumeric part at the end, as highlighted.
Click the youtube button top right and paste between {youtube}and{/youtube} thus:

[youtube]MMLXoobDKWs[/youtube]

Good luck!