I have added the ability to post youtube videos within posts.
You have two options:
youtube url - such as "http://www.youtube.com/watch?v=pLRZp5sT3AA"
or
youtube video id - such as "pLRZp5sT3AA"
Each option has its own button when posting.
[youtube_video_id]pLRZp5sT3AA[/youtube_video_id]
Cheers!