Hello all, first time poster long time lurker here.
I also got the call on Friday! I'm sure those of you who also got it can relate to the relief after living with this application for a year.
As far as the medical goes, you need an "Aviation Reference Number" (ARN), which we'll get in due time. I'm not in any rush.
For those interested, here is a rundown of what you need to pass for the medical: http://www.austlii.edu.au/au/legis/cth/consol_reg/casr1998333/s67.160.html
It doesn't look like you have to be an elite athlete, just someone who isn't going to drop dead at the controls.
Congratulations to my new colleagues and good luck to everyone going through the testing now. If you're in the latter group, just remember patience is the name of the game.