append values to drupal7 cck link field entry
You can use the Media: Youtube module.

You would then create a file field with a Media file selector widget. Make sure you configure the field to use the Youtube URI schema.

You can configure the size of the video through the field display settings.

When you create a new node, you will need the share url, like http://youtu.be/n1yxNjU7u_8 to embed it.