WordTwit is a plugin that utilizes the Twitter API to automatically push a published post to your Twitter account as a tweet, using the blog domain as a short URL.
With drop.io you can easily send any media or content you want to all your twitter followers by just adding it to your drop. Create a drop here by clicking 'drop it' - then just add your twitter account and customize your tweets... whenever you add new content to the drop via any 'input' it will be instantly tweeted.
Publish full articles without needing a blog or site. There's no setup or login. Just write your text and Write4net will publish it using your Twitter account.
A few bit.ly users who also heavily use Delicious and Twitter have asked for an easier way to sync all these services. We recently came up with a pretty good way to automate this sync process using Twitterfeed.
This site provides a simple bookmarking service. We follow your twitter feed, and whenever one of your tweets contains URLs, we add them to your delicious.com bookmarks. Optionally, bookmark URLs in @replies to you. We'll even add a delicious tag identifying the sender if you like.