Plato has a nice email interface you can access through any browser with an internet connection.
Simply visit webmail.webhost.co.nz
To log in, use your full email address as the username, and then the password you either chose or we supplied you with. You will be able to check, reply and send new emails, along with store a contact list online. Just be sure to log out when you're finished so no one else who might use the computer can access your emails!
As it's probably a lot easier to remember, you should also be able to visit webmail.yourdomain.co.nz to access the webmail interface. eg. webmail.johndoecorp.com