Twiggit is a great service to promote article at Digg. You have the option to only Tweet aritcles that you submited. It is pretty simple, all you do is to provide them with your Digg ID, Tweet account and email.
Once you digg, it should appear on your Twitter. Unfortunately it is not quite instand. But it is good enough.
This would be another way to promote your Digg submission.
