Thanks to Livvy for this.
Don't use the embedded link on Youtube.
Goto the top of the page and copy the link in the address bar.
http://uk.youtube.com/watch?v=OK9sSafErjg
Delete watch? and replace the = sign with a /.
Now wrap this link with the flash tags
, you can also increase the size of the embedded link by changing the 200,200 to 500,400.
Ala.
[flash=500,400]http://uk.youtube.com/v/OK9sSafErjg[/flash]
Don't use the embedded link on Youtube.
Goto the top of the page and copy the link in the address bar.
http://uk.youtube.com/watch?v=OK9sSafErjg
Delete watch? and replace the = sign with a /.
Now wrap this link with the flash tags

Ala.
[flash=500,400]http://uk.youtube.com/v/OK9sSafErjg[/flash]