When setting up a new hosted email domain in Zimbra, storeitoffsite.com can assist in the account creation process with a "bulk load" method as follow:
Using your favorite text editor such as notepad (Mac, Linux or Windows) create a file following the below format. Each line contains the basic account information for each address that you wish to create. Save the file and email to us, and in a flash, we'll have all your accounts populated and ready to accept mail.
createAccount email@example.com password displayName 'Andy Anderson' givenName Andy sn Anderson
createAccount firstname.lastname@example.org password displayName 'Betty Brown' givenName Betty sn Brown