Twitterfeed is free to use and very easy to set up. Just create an account and paste your blog's feed URL into the text box provided to set up a new feed. You can also configure advanced settings such as a snippet of text to appear before the automated tweet (such as "New blog post"), frequency of updates, what tool you want to use to shorten URLs, if you want to tweet the title of your posts and snippets or just titles, text to appear at the end of tweets, and more. You can also view simple statistics to learn what links are generating clicks on your Twitter profile.

Twitterfeed does what it claims, and it does it well. If you want more advanced features, then Twitterfeed might not offer everything you need, but to simply automate the process of updating your Twitter stream with links to your blog posts, Twitterfeed is a great option.