If you want to embed youtube videos in your post, just cut and paste the entire link as shown below which includes the http at the front: http://www.youtube.com/watch?v=UtQragQ_CEo - URL address posted as a link (will not show as video)
http://www.youtube.com/watch?v=UtQragQ_CEo The actual address you see above is posted as a link and will not display as a video below it. If the link you pasted shows as a link and not a video, you will need to highlight the entire link and select the Unlink button on the edit bar above your text then click Save Changes.
After you click the Unlink button it should appear with no underline:
(If you are going back into the post to edit, you need to select the "Use Full Editor" button at the bottom of the edit window in order to have the Unlink button available.
-Webmaster