Customer e-mail announcement list

We are interested in building an e-mail announcement system where our customers can subscribe to receive emails. This could either be a custom-built solution, or if there is an existing product that fits our needs I would pay for that information. I've attached a better-formatted version of the spec with this post. Our current system fulfills most of our needs but is not scalable and the company that built it for us is no longer available to edit it, so we are looking into a new solution. Requirements are as follows: 1. Categorization a. The lists must be categorized first by school, such that we can choose between managing and adding different schools. i. Must be scalable so that we can easily add schools later on ii. Examples: University of Florida list, Florida State University list, University of Indiana list, etc b. Next, there will be specific classes within the schools. This is where the contacts should actually be stored. i. Examples: Introduction to Accounting, Managerial Accounting, Chemistry, etc 2. Users a. Administrators should have the ability to create, manage, and assign accounts and permissions for users to be assigned to a specific school and/or classes within that school 3. Email abilities a. We would like the ability to use a WYSIWYG editor, but also an HTML insert option if we want to use advanced HTML templates or code. b. We would like the emails to send from our domain, [login to view URL] 4. Subscription a. We would like the ability to post a subscription button on a webpage to give the students the option to enroll in a particular class list for a specific school, as well as the option to subscribe to our newsletter b. Further, we would like the ability to simply post up the “school” category page and allow users to choose from all class lists available for that school c. Students would need the ability unsubscribe from the list easily with an unsubscribe list 5. Clearing Out a. We require the ability to download individual lists as an excel document b. And the ability to download all lists together c. Since we operate on a semester schedule, we need an option to clear a particular list or all lists at any point