If you are using Google Apps (or it's little brother Gmail), you can follow the "Multiple Choice" questions at:

For those wanting the quick answer...
Outgoing Mail (SMTP) Server - Requires TLS
  • smtp.gmail.com
  • Port: 465 or 587
  • Requires SSL: Yes
  • Requires authentication: Yes
  • Use same settings as incoming mail server

Not using Google Apps?

If you are not using a hosted email service (e.g. if it's on the exact same server as your website), it's recommended that you use your ISP's SMTP settings.

  1. BigPond / Telstra  (including Telstra mobiles)
  • SMTP server:  mail.bigpond.com
  • Optus (including Optus mobiles)
    • SMTP server:  mail.optusnet.com.au
  • ...
    • (More coming soon!)