Auto-Responder Opt-Out

We currently have users that subscribe to receive emails. Emails are fired off based upon cron job that runs each day. We need to add the ability for the users to unsubscribe from receiving these emails. I suggestion. Adding a field to the database called "subscribed" with a basic Yes/No. The unsubscribe script will trigger this field and the send script will not deliver mail to anyone with NO specified. We will need to add the unsubscribe link in the footer of all emails. Thanks