If you use an autoresponder software that does not have unsubscribe features, how do you process unsubscribe requests externally? What program, software, removal script and unsubscribe form do you use?
Most autoresponders should come with built in unsubscribe feature. If your current provider does not support it, consider changing provider - there are lots out there to be stuck with one. That said, if you were running your own custom script, adding unsubscribe feature is a straight forward process. In the unsubscribe link, add the user unique ID and email; and when clicked run your unsubscribe feature directly on your site. Please note that you have to add security features so that your system is not abused by mindless users. PM me if you still need help.
If your service doesn't offer it, try http://mailchimp.com. Reasonably priced, free up to 500 users, and reliable.
Thanks @gacba,I will check out mailchimp as I have a little mailing list that I run. I have a custom Python app I currently use for all my subscription, it is simple but effective and does the job. I won't mind checking out something more professional though