WP-SNAP! (WordPress System for Navigating Alphabetized Posts) creates an alphabetical listing of post titles on a Category or Page template file. Navigation through the listings WP-SNAP! generates is accomplished using the alphabet itself. (For example, if a site visitor clicked on the letter D, any post titles that began with that letter would be showcased.) WP-SNAP! will work on any WordPress 2.5 or higher site, but is particularly useful managing glossaries, indexes, reviews, or directories.
WP-SNAP! offers three different navigational styles and integration with both custom permalinks and the WordPress loop. Plugin options can be managed both site-wide and on the template itself with results either restricted to one category or broadened to include child categories as well. The clever web developer should have no problem seamlessly integrating WP-SNAP! into their latest project. Options have also been added to allow the customization of css class names and the appearance of html mark-up.
Plugin Documentation: http://wordpress.org/extend/plugins/wp-snap/