How do I unsubscribe from a list?
Generally, the easiest way to perform common actions on a list is to use the list's Info Page, which is located at http://www.freelists.org/list/LISTNAMEHERE.
You can also unsubscribe by sending email to LISTNAMEHEREfirstname.lastname@example.org with “unsubscribe” in the Subject.
Obviously, both of these methods require that you know what the list name is. If you don't know, just look at where the messages you're receiving from the list are being addressed. The To: header will contain LISTNAMEHERE@freelists.org.