well, you will need a dns server for that. I've my own mail server, and my own domain, and i dont have a static IP. using no-ip.org, i'm able to have a dinamic dns, a working http server and a working mail server.
visit the following site. it's excelent. Remember, when setting the email server, don't forget to install also Mailscanner and a good anti-virus (clamav is excelent). everything is opensource and GPL (or some sort of).
The site: http://www.linuxhomenetworking.com/#Linux