The posting address is sca-mists@thibault.org, the subscription address is sca-mists-request@thibault.org.
I have just gone from using a homegrown mailing list package (all I could manage at my old ISP) to majordomo. For instructions on how to subscribe, send a message containing the word "help" in the body. (I'll put actual instructions here Real Soon Now, but it's late and I realized I needed to put something accurate up here.)
The list maintainer is Francois Thibault, sca-mists-admin@thibault.org.