And you'll also need a no-ip address reporter, something like no-ip.com or dyndns.org offers. That tells the DNS what your current IP is. Anyone with a cable modem or non-static DSL has to use them to report their address, but seeing as your address will change VERY often on dialup, you'll need one of those. I know dyndns.org has a free service, and expect no-ip would as well.
It makes no sense to have email on a dial up connection however. When one email server tries to connect to another, if it fails (because your modem is offline) the sender drops the mail into a queue, and it tries again at set time periods. You'll miss a lot of mail people try to send to you, and I strongly suggest you don't try to run a mail server on dial up.