My last blog with regular weekly posts, interactb.in, ran on Tumblr, which has a great Twitter integration where you could post custom tweets to send out when a post was published.
In looking for similar functionality I settled on the premium plugin, WordTwit Pro from BraveNewCode. What this plugin had that a lot of other ones didn’t was a way to send a custom tweet with a post so I could @ cc companies or products mentioned in a post.