How to accomplish a working Unsubscribe functionality?

[tillkrueger]

What is the process to create a working Unsubscribe link? The page that the link goes to needs to communicate with SendPortal via API or is there a simpler method to remove a Subscriber from the list of our Newsletter?

We have used the {{unsubscribe_url}} method (to link to a page that doesn't yet exist) because we don't know what that page needs to contain to remove a subscriber from our newsletter mailing list.

Any help would be greatly appreciated.