Jackson Whelan

Allows you to paste iframe codes in the visual editor, just enclose within the [iframe][/iframe] shortcode.

iframe Shortcode

Paste iframe embed codes into the visual editor.

flynsarmy

Allows the insertion of code to display an external webpage within an iframe. A WYSIWYG button is included to make adding the code easy.
See the ‘Other Notes’ tab for usage information.
<h3>Usage</h3>
The tag to insert the code is: 
 [iframe src=”http://yoururl.com” width=”100%” height=”600″]
You can use any attribute and it will work.

IFrame Shortcode

Allows the insertion of code to display an external webpage within an iframe.

Requires PHP 5.3 or later.

iframe Shortcode vs IFrame Shortcode