QUOTE (eddy2099)
Are you trying to replicate what hotmail.com does by allowing anyone who visits your site to create an email account with web mail access ?
Hotmail isn't a very good comparaison

But yes, something like that, with POP access and webmail... If possible with PGP (or GPG) support....
A good mail service like that is www.mailvault.com, but there soft is very expensive, I am quite (?) sure there's some open projects somewhere, but coul;dn't find anything!