Here is a list for blog directories where you can submit your blog, drive traffic and create backlinks. If you also know about some blog directories then feel free to mention it here so that others could also get benefited from your knowledge.
Tweetily – Tweet Your Posts Automatically! is the best plugin for auto tweeting your WordPress posts. Easy to install, easy to connect with twitter, automatically promotes your posts and pages on Twitter, keep your content alive and drive traffic to your site. Works better than Tweet Old Post Plugin. Set it and forget it!