i dont know if everyone already knows how to embed youtube clips but as i`m proud of myself because i`ve worked it out (and i`m usually cr@p with computers) i`ll try to explain how to do it for anyone interested.
when you post a reply, across the top of your reply message box there`s a line of functions, press the youtube function on the top right hand side.
then 2 tags appear something like these 2 - [ youtube ][ /youtube ]
between the tags you have to write the ID string or the code of the youtube clip you wish to show but you dont write the whole thing out. for example here`s a youtube clip ID string in it`s entireity -
http://www.youtube.com/watch?v=WbrjRKB586syou dont need to include the `http;//www.youtube.com/watch?v=` bit of the ID string, infact it wont work if you do include it, the bit you need is the remaining part of the ID string, in other words just type out `WbrjRKB586s` between the 2 tags.
some clips have `&feature=related` at the end of the ID string, just erase that part of the IDstring.
hope this helps, sorry for not making it a bit more clearer.