The Twitter Tools Plugin, which again is available from the dashboard of your blog, allows you to connect your blog posts to a twitter account. You can create an automated process so that every time a new blog post is published on your blog, an update with a link is posted on Twitter.
When you set up this plugin, be sure to go back into your twitter tools setting to make sure that the Application Type has read and write access (http://wordpress.org/support/topic/plugin-twitter-tools-it-works-make-sure-twitter-application-has-read-and-write-access).
Here’s a screenshot that shows the look of the resulting twitter account posts:
As you might notice, I activated the companion Twitter Tools: bit.ly links plugin to create shortened URLs (useful on a platform like twitter that has a 140-character space limitation).