IFRAME Embed For YouTube will add a quicktag on WordPress Post Editor which will add the capability to embed Youtube Videos thru IFRAME, just you need
As we have developed this plugin to make your life easier that’s why we have made the process to use this plugin very simple. On Dashboard, you can see “IFRAME Embed for YouTube” tab under Settings section. On settings page of this plugin, you can set the default width and height of the player. You may set value as per your theme template.
To embed IFRAME code of YouTube video on a particular post, open the post to edit. Now you can see a player like icon on the tool bar of Visual format of editor. Once you will click on that red color icon, that will ask you to enter a URL. Copy the URL (link) of the YouTube video which you want to embed in post and paste the URL in quick edit box. Click on “Insert” to get the [yframe] tag with URL in the post. Done, now you can save or publish the post on your blog and you can see YouTube video embedded with the latest player of YouTube (not the old flash player). Now you can see the page source of your publishes post and find the embed code for YouTube video as IFRAME. Repeat this procedure to embed another video on your blog post or page thru IFRAME embed code.
Go to the plugin page to see more details (http://www.clickonf5.org/iframe-embed-for-youtube)