It's a breeze. Using dlvr.it, you can start auto-posting your blog to Twitter in a minute or less.
Three steps to start posting your blog to Twitter:
1) Go to dlvr.it and create an account with your email and password.
2) Enter your RSS Feed URL and click Connect on the correct search result
3) Click on Connect New on the next screen and click on the Twitter icon to connect your Twitter account. Click on Start Posting.
That's it! dlvr.it will now automatically post your new RSS items to your Twitter account.