We are due to fly from Sydney to HCM early April, but on checking the dates again on the website, there are only Jetflex listings ($1,000+ one way) for flights after March 2009.
I rang Jetstar, as we have already booked & paid, and they said that they are contacting all passengers (batch by batch) to notify them of the change - don't know what it is though, and they would not elaborate on the phone.
They just said to wait until Jetstar contacts us.
So,if you have already paid for your flights for a trip commencing after April, 2009, just wait for your call from Jetstar.
It may be wise not to make any domestic internal flights or paid hotel bookings just yet.
Will keep our fingers crossed.