Tutorial by Twb6543:
First on the post create a new flash element (there is a button called insert flash)
changing the width and height correctly (default for youtube embed videos is 425,344, default for flash is 200,200)
[flash=width,height][/flash]
Next copy the video url from youtube (really you should comp it from the embed code but this still works)
http://www.youtube.com/watch?v=bgthOv9IQ-E
We now need to change it a little:
we need to change the url from /watch?v=CODE to /v/CODE as this is the actual video
Also remove any extra url parts like &fs=1 or &feature=channel, etc.
so
http://www.youtube.com/watch?v=bgthOv9IQ-E
becomes
http://www.youtube.com/v/bgthOv9IQ-E
next paste the new url into the flash element like so
[flash=425,344]http://www.youtube.com/v/bgthOv9IQ-E[/flash]
and you should receive something like this (remember to place the video in a spoiler for slow internet users)
Quotehttp://www.youtube.com/v/bgthOv9IQ-E
Unfortunately two spoilers won't work together at the moment so the videon is now in a quote.