The Gunner Technology Shortcodes plugin gives you the ability to add a widget anywhere you want.
When you add a widget in the widget panel, you’ll see it has a shortcode at the bottom. You can take that shortcode and copy and paste it into a page, post or even another widget.
For questions, comments, and feedback, please go to our blog post: Shortcodes WordPress Plugin
Requires WordPress 3.0 and PHP 5.