How can I create a mailing list that can only be posted to by its members?

[beanmg]

 

I run a club web site (Apache, PHP, MySQL) and I would like to start an e-mail distribution list.

 

The only specific requirements for this will be that

 

i) it is e-mail based

ii) only club members can e-mail to it

iii) it is relatively easy to install and administer and

iv) its free!

 

So, I don't want one of the many mail-shot products, this must be controlled many-to-many mailing within my group.

 

This/these must exist but I can't be using the right keywords in my search.

 

Can anyone help?

 

beanmg