198307 newsletter / notifier script

I am hoping to find something existing that will require little modification to do what I want it to do. The script I am looking for will allow people to visit my site and sign up to recieve newsletters and info that they opt-in for. They will enroll on a form and then make a selection of areas of interest. The script will store all this information and then when a newsletter or news item comes up that the subscriber has indicated they want ... it automatically sends it out to them. So Admin would input the newsletter, say what it is for, and then the script would identify the recipients.