Email distribution list and send out event reminders (posts?)

Have to admit to being a bit of a WordPress noobie.

First requirement I have come across that I do not know how to best deal with is sending out email reminders of forthcoming events.

The client wants to be able to enter a relatively static list of email addresses and send out a reminder email to all of these now and again. It may even be desirable to allow the customers to add their own email addresses to the distribution list.

At the moment this site does not use WordPress Posts for anything. What is the best way to achieve the above requirement, can it be setup so that this is done by adding a post and having that somehow emailed to the whole distribution list? Failing that is there a Widget that would allow an easier way of sending group emails instead?

Thanks,
Nick