well what i want is for users to be able to go to a site and set up an email for free at domainname.com instantly, and then I want to be able to customize the email browser thing
I have a script that allows people to join like gmail does. It isn't very advanced, it can only: allow people to register, login, read, reply, forward & delete email, and compose it. It has no contacts or calendar, but other than that it's pretty cool. It only requires one email account on a whole server to run, since it makes "virtual accounts" using the mysql database and php to determine who gets what emails.