Email settings can vary depending on your package, the setup of your email system and your internet connection.  You must first create the mail account in your control panel.  For instructions on how to do this please see the tutorials at:

http://www.gohosting.com.au/faqs/index.php

For basic email client configurations:

Incoming Mail Server:  mail.yourdomain.com (eg: mail.gohosting.com.au)

Outgoing Mail Server:  The SMTP server of your ISP OR mail.yourdomain.com (eg: mail.gohosting.com.au)
NOTE: Many ISP's block Outgoing port 25 so you must use their SMTP server or manually change your mail client to use port 26.

Username:  The full email address of the account (user@yourdomain.com)
Password:  The password you created for the account in your control panel