DNS2Go

From Deerfield.com:

DNS2Go allows you to name your space. It's the perfect service for those seeking to leverage the true potential of their computer and Internet connection. Host your own website. Host an FTP server so that you can exchange files with family and friends. Host your own email server and provide everyone in your family with a highly personalized email address.

DNS2Go is easy to use; you can sign up for a DNS2Go domain, or you can register your own top-level domain. If you decide to use a DNS2Go domain, you'll have no less than twenty-five sub-domain options to choose from.

The DNS2Go client software is installed on the computer with which you want to associate your domain name. The software always knows your computer's current IP address, and it quietly and automatically notifies the DNS2Go service whenever that IP address changes. The DNS2Go service then modifies the DNS zone records associated with your domain, and the change takes effect almost immediately. The bottom line is that anyone typing your domain name into a web browser or other client software will be led to your current IP address. No matter how often it changes.