While this is not really a tool, it was far to good to pass up. All credit to the blogger, Twilight Fairy, that posted this and this is only an excerpt to get it out there. It seems reports are now coming in that Twitter detects this and it will not work. But one for the toolset just in case.
To send a DM to anyone who’s not following you, just “derive” their URL to create a DM message.
The URL would be http://twitter.com/direct_messages/create/<username> where you need to replace the <username> with the twitter id. for eg. to send a DM to me, you would use the following link: