This is what I was searching for: http://www.firesidemedia.net/dev/software/wordpress/twitter-updater/.
The Twitter Updater automatically sends a Twitter status update to your Twitter account when you create, publish, or edit your WordPress post. You can specify the text for the updates, and also have the option to turn the auto update on/off for the different post actions in the admin panel.
Find more WordPress plugins at http://wordpress.org/extend/plugins/!