twitter direct message automation

is there a script out there that can automate sending a direct message out to my followers?

I'm aware of tweetlater but that will only send messages right after they follow me.

I want to send the same message not as a tweet but as a direct message to my followers so that they can see my offer to them (giving them for free a book that charge $47 for)

I know tweet later will do this when someone signs up to follow me, but I'm looking to message them automatically after that has happened.

thanks for any guidance

 

Try out using this; http://tweetmanager.com/

 

There are a few, I don't use the one linked above but I don't remember what it was that I setup

Here are over 100 twitter tools

 

thanks Bob and Loco,

Tweetmanager is closed right now and I'm on the list but I'll check the 100 twitter tools to try and find something on there, it's gonna take some time to look thru all of those links.