I'm testing a modification to allow you to embed videos from youtube.com into your forum post. If you find a video on youtube (or even better you MAKE a video and put it on youtube) then you can put the video into your forum post directly, instead of a link.
So to use the function you can click this button (http://www.alfaclubvic.org.au/smf/Themes/aroca/images/bbc/youtube.gif) then put the id of the youtube video inbetween the two "youtube"s in brackets.
[youtube]<id goes here>[/youtube]