You can do so by going to this site and select 'Subscribe' and following the instructions there. You can also 'Unsubscribe' there. After your registration is approved, you can start sending messages to

schism_list@vims.edu

Note that without registration your message would be treated as spam.

You can easily search for archived messages on the same web. Just log in (you may need to register yourself there first), and then from the dropdown list under your name, select 'My lists' and then under either schism_list or schism_dev, select 'Archives' (you can also select list name first and then select 'Archives' from the left of the screen). You can browse or 'Advanced search' the archive.