Open your YouTube home page. Then use the 'Search' box in the menu at the top of the page to find the song you want to embed on your Facebook Wall or send as a message to a friend.
When the YouTube video page opens, click on the word 'Facebook' below the video, in the second row of the menu.
When the Facebook-Share Window opens, click on 'Post to Profile' to embed the video on your Facebook Wall then type a message in the 'Whats on your mind' box. Next click on 'Share'. Or ... to send video to a friend, click on 'Send a Message' to embed the video in the message to your friend then type a message in the 'Message' box. Next click on 'Send'.
To see the YouTube video on your Facebook Wall, open your Facebook to your 'Profile' page.