I uses this excelent guide to set up my email server some time ago.
I have no registered a second domain name and was wondering what changes are required for the original and the new domain name to work concurrently.

ie
Zone files on domain provider have both domains pointing to same IP address.
Would want for eg This e-mail address is being protected from spam bots, you need JavaScript enabled to view it and This e-mail address is being protected from spam bots, you need JavaScript enabled to view it to end up at same name account on email server etc

Thanks