Tweet Old Posts randomly picks your older post based on the interval specified by you. The primary function of this plugin is to promote older blog posts by tweeting about them and getting more traffic.
Displays your latest pictures from TwitPic in the sidebar of your blog. The plugin is widget ready and comes with many configuration options such as customizable css file.
The WP-to-Twitter plugin posts a Twitter status update from your WordPress blog using your selected URL shortening service to provide a link back to your post from Twitter.
Integrate TwitterCounter.com badges on your blog to display the number of followers you have on Twitter
Tweetable is intended to help integrate Twitter into your blog. It can automatically tweet links to your blog posts as they are published. It can display your latest tweet in your sidebar and add a tweetmeme widget after your posts. You can even use it to share a Twitter account among a blog’s author’s if you wish.
Provides a Twitter retweet button for your posts that shows all tweets, enables retweeting, and adds tweets as comments.
Your very own TinyURL within your own domain. If you do promote your blog posts in Twitter, then you must make your links look cool.
Provides several Twitter widgets: show your own tweets, show tweets relevant to post’s tags, show tweets for Twitter lists, show tweets for hashtags and more.
Twitter Fans lets you display your twitter followers in the sidebar as a widget just like Facebook’s fan widget in appearance.
Simple Twitter Connect is a series of plugins that let you add any sort of Twitter functionality you like to a WordPress blog. This lets you have an integrated site without a lot of coding, and still letting you customize it exactly the way you’d like.
Twitter Comments system. Automatically retrieve Twitter Replies and/or Twitter Retweets to your Blog’s Posts using WP built-in comment system.
Easily allows your blog post or page to be retweeted. It provides a live count of how many times your post/page has been retweeted throughout Twitter.
Twittar WordPress plugin main objective is to create a plug-in that uses Twitter to show avatars in comments in WordPress blogs.