If you don't mind a little advise from a newbie to the forum, I would
be very careful in offering free email.

First, you ISP and server provider could experience overload.

2nd, by providing this kind of service, you leave your self open
to legal problems involving "spam", harassment, etc..

In my experience, most "FREE" email offerings have lost their
appeal since the internet already offers free email account through
(hot mail, mail to, amex.com and more) many providers.

Hope this helps.