HOW TO POST YOUTUBE VIDEOS
1) Paste the URL of the youtube video (the address in your browser's address bar, not the embed link youtube gives you) in your post...make sure you include the 'www'.
2) Delete the '&' symbol from the URL (if there is one) and everything to the right of it.
The URL should look something like this: http://www.youtube.com/watch?v=iHXx4WwqmSY
3) Highlight the URL you pasted in your post and click the youtube button to apply the youtube tags.
4) Make sure you do NOT have the "Disable BBCode" option checked.
Your video should look like this after submitting: