To embed youtube videos you have to use tags, like these ones:
[ yt][ /yt] -with no spaces-
you can click the button at the upper right corner of the menu where you set the font and all that in the reply window, its a blue
YT, you click on it and it will give you the embedding tags for youtube videos.
On youtube when you have picked the video that you want to embed, you copy the url address in the address bar of your browser, [example http:/www.youtube.com/watch?v=
nfUjfioAnKY] and you copy only the last -
highlighted- part of it and put it in between the tags like this
[yt ]
nfUjfioAnKY [ /yt]
with no spaces in between, and its done.
Embedding the videos here doesn't seem to work for some reason.
Thanks for the link Ash. 