@Spoon
Use this Lewis Black vid as an example:
[nomedia="http://www.youtube.com/watch?v=LGrlWOhtj3g"]YouTube - Lewis Black - The Old Testament[/nomedia]
You would take LGrlWOhtj3g (the letters after v=) and plug it into [youtube][/ youtube] without the space in between / and youtube (or just press the youtube button

) to get: