http://wpsmith.net/wordpress/how-to-widgetize-the-home-page-of-the-expose-genesis-child-theme/

http://digwp.com/2010/02/how-to-widgetize-wordpress-theme/

http://wpmu.org/how-to-widgetize-a-page-post-header-or-any-other-template-in-wordpress/

http://digitalraindrops.net/2010/08/widgetized-areas/ (NOTE: some of the code is NOT perfect. If you experience a broken site, double-check the PHP)