Your wing, harness (with reserve), helmet and gloves are all you really need to go flying. However, there is an almost endless list of other equipment and software available.
You really should have one—and it should be certified for use in Australia:
UHF to start with
Airband VHF later when you get into XC flying
For more information, see Fly Manilla.
Not really needed by new pilots who don't need that sort of distraction. However, excellent software is available for your phone:
Android: XCSoar / TopHat
iPhone: Flyskyhy
Many simpler apps are also available.
