Twitterfeed can help build traffic to your blog. Just give it the RSS feed url of the blog. It will check for new posts on a schedule of your choosing, then post the first 140 characters to your Twitter account automatically, with a link back.
You can do this with any RSS feed. One tip: Don’t just do this. You need to be posting to Twitter manually too. That’s where the fun and feedback happens. A Twitter account that only auto-posts won’t be followed as much as one where there is active tweeting, along with auto-posting.