I've got to set up a mailing list manager for one of our users.
She wants to send out a quarterly newsletter to all of our customers. She was just going to add all the addresses into the To or CC fields!

Luckily I found out in time and managed to stop her!
The next step is to find some "proper" software for generating a proper newsletter and sending it out to all the addresses in the list. I want to eventually add a form to the website, where the users can request or cancel the newsletter.
Has anyone any experience with a decent mail generator? I'm guessing it will have to cope with around 250-300 recipients and should ideally work with AD / Exchange (to get the email addresses), although it can also work directly through SMTP for sending and have a manually generated list if necessary.