Auto Tweet adds a check box to the Write Post editor (both the TinyMCE/Visual Editor and the advanced editor).
When this box is checked, publishing your post will also send the post to Twitter.
If a post is longer than 140 characters, it will be truncated.
Auto Tweet creates a new column in the “posts” table of your database to mark which posts have already been submitted and will use that information to help prevent double-posting.
Free Download: Download this wp-plugin