We now have Youtube embedding. Additionally, we've got Google Video embedding, and I may be able to setup embedding for other sites too, if you have a favorite video site from which you want to post videos.
To use Youtube embedding, you'll need the Video's ID number. You can find it in the URL for the video. Then you surround it with <YT> and </YT> tags (except using square brackets).
So, to embed this address:
you'd use this code:
and the result would look like this: