Everyone, including me, is having trouble with this, but I think I have it figured out. To post a video:
- Use the flash tags, and change "200,200" to "425,344"
- Copy and paste the URL of the video between the flash tags. Not the whole pasting code you used to, but just the URL-- in my case this is http://www.youtube.com/watch?v=eVfHieBITxk
- replace the "watch?v=" with simply "v/"-- this will point to the standalone video location and not the youtube page
In the end, it should look something like this:
[flash=425,344]http://www.youtube.com/v/eVfHieBITxk[/flash]
And the result is this:
http://www.youtube.com/v/eVfHieBITxkOne more note-- the URL change made above is what youtube actually gives you in the "embed src" tag in the code you used on the old board to copy and paste. If it's easier for you to grab the URL from there than to make the change, it ought to work.