WP Custom Taglines adds a meta box to your posts and pages with two options, Enable Custom Tagline, and Custom Tagline Content. Checking
“Enable Custom Tagline” will cause your site to display the contents of the “Custom Tagline Contents” field on your site when that post or
page is viewed, instead of the sitewide tagline.
Check out http://www.workinginboxershorts.com for more plugins, for support or questions, or to contribute code.