Name: Wordpress Text Message
This plugin allows people to signup for SMS text message updates from your WordPress web site. Just drag the sidebar widget allowing people to signup from the front end, or manually add subscribers from the plugin settings page. You can even set an option to "send out text updates every time a post is published", which is great for small business owners, organizations, performance artists, etc.
License: GPL v3
Wordpress repository plugin page: http://wordpress.org/extend/plugins/wordpress-text-message/
Author plugin page (with screenshots): http://www.jtpratt.com/wordpress-plugins/wordpress-text-message/