To a video from Youtube
* Get The URL Code here is an example http://youtube.com/watch?v=P4Z6n9ECXHw
* Now you will need to delete the "watch?v=" Eg http://youtube.com/P4Z6n9ECXHw
*Now add /v/ after the .com eg http://youtube.com/v/P4Z6n9ECXHw
*Now click on "Media" in the code buttons area.
*Now copy the link you have made into it. and click ok
*Now enter the width normally "425" and click ok
*Now enter the height normally "350" and click ok
*Now your video will play in your post.

If you have any problems please feel free to PM me.