I've added this site to Twitter at http://twitter.com/webmastertips.
Drupal has a Twitter Module, but it doesn't come with any documentation. This post is a first test of Drupal's Twitter Module on this site. If it works, I'll follow up on this post.
UPDATE: The Twitter Module for Drupal works. Here is some documentation for it:
Once you have followed those five steps, every time you post to your Drupal site from that user account it will add the post to your Twitter account.
An alternate method for auto-posting to Twitter that I prefer is Twitterfeed. The difference between the Drupal Twitter module and Twitterfeed is that the Drupal module allows all your users to post their own content to their own Twitter profile. Twitterfeed is a 3rd party service that has to be manually setup for each feed.
By the way, check out this comparison of icons from Drupal (top) and Twitter (bottom).