how to add new service name?

I still new using Oracle database.I want to create the new service name of my database server.How to change it?For your information,I want to add the new database server service name,I need to change it using Oracle client 8i or Oracle administrator? I want to change the service name for Server not the client pc. :confused:

I hope some one can advice me.

none of that makes any sense whatsoever