Send mail to listserv@sun.soe.clarkson.edu (not to djgpp!!), leave subject empty and in the body write:

add <your e-mail address> djgpp

add <your e-mail address> djgpp-announce

Note that you don't have to subscribe to djgpp mailing list if you don't want to get all the traffic in your mailbox (typically, about 10-20 messages per day). You can ask questions on the list even if you are not a subscriber, because people usually answer both to your e-mail address and to the list (well, actually, the mailer program does it automatically and most people don't bother to change that). If you want to be sure the mail gets to you directly, say in your message that you don't subscribe to the list, and ask people to answer directly.