I was successful in posting a video link for YouTube (http://www.youtube.com/watch?v=EwqmB3Jocmw) once. I had followed the instructions posted in the forum and: bingo! It worked!
But then I had to go back and edit my post after publishing and the video has disappeared. I repeat the linking functions, but nothing seems to work. I see the link as a URL when the Edit Post page opens up. But I can't even see the video freeze-frame in my Preview Pane. What's goin' on?!
Take a look here: http://sonofspam.wordpress.com/.