If you have a blog and want to publish all your new posts to Twitter automatically, the best tool to use is Twitterfeed (@twfeed) (This actually works for any RSS feed).
As their slogan says, “twitterfeed: feed your blog to Twitter”. Once you’ve set your account, just add your RSS feed(s), your Twitter account, and all your blog entries will be tweeted (with a link to the blog of course).
Only problem is that this takes time, unless your RSS feed is published in real-time. A few blogging platforms (notably Blogger) are now using PubSubHubbub (aka PUSH) to do that. Twitterfeed just announced a week ago that they now support the standard, which means that your post will be tweeted in real-time (and not hours as before).
Blog posts -> RSS feed in real-time -> Twitter in real-time
Good to see that you can write long posts in more than 140 characters, and they’ll be broadcasted via Twitter in real time.
Twitterfeed is going to support RSSCloud (Wordpress compatible) very soon.
We’ll shortly be announcing support for RSScloud too, so that wordpress sites can also be published in real time.