When I turn on Personal File Sharing in System Preferences, it says

"Other Macintosh users can access your computer at afp://xxxx/ or browse for "TiBook" by choosing Network from the Go menu in the Finder."

The afp:// has my old computer name written. And I wanted to change it. I think its stored in the DNS because I have tweaked the DNS numbers and it has changed back to my IP Address. Any ideas?