It is quite possible this is an advertisement for casual cabin crew that Jetstar will soon be hiring.
I'm Team Jetstar cabin crew currently and we have been told by management that to effectively cover peak periods of flying (ie. school holidays/Christmas), Jetstar will be employing a pool of casual cabin crew which it can call upon during these times. Recruitment of permanent full-time crew to the Team Jetstar operation will still continue alongside.
They said they were expecting to be hiring the casual crew around Jan or Feb (2010). So it fits that this ad may very well be for JQ. But who knows!