To embed YT video's you need to "like" the video, and enter the URL into the post. Second, you need to wrap the URL with the "[ youtube]" "[/youtube]" code.
You actually don't need to "like" the video. Just copy the URL from the address bar and put it between (Youtube) (/Youtube) with square brackets, like Kareem said.
Well , I guess the difference between my second link and Kyle's link is the feature=player_embedded stuff, but my first one used to work in the by the same method mentioned of liking the video and sharing the link