It's not clear if you want/need a mailing list server solution or simply a way to manage maling lists/groups at the email client end of things? If it's the former then the links in this Wikipedia article might be of use. If you are going to create an email client mailing list/group then make sure to respect the privacy of recipients (e.g. by not divulging their email addresses to other mailing list subscribers if required). Hopefully you're not going to be spamming people?