Never fly Jetstar from Sydney to Melbourne.
In their infinite wisdom, Jetstar ran the flight from the INTERNATIONAL terminal for a DOMESTIC flight. If you don't know the seriousness of this, allow me to summaries the highlights:
1) No web check in, even if all you have is carry on luggage. You must front up to the airport extra early so you can claim your boarding pass after you present ID.
2) Queue up with all the other international passengers leaving Australia. Congrats bitch, even though this is a domestic flight you'll be going through FREAKING PASSPORT CONTROL!