jamesf said..
If you haven't already booked your flight, try to go with Virgin or Qantas instead as they take longer bags on the 737. The 2.3m limit on the Jetstar A320 could be tough to fit even a board bag in. Plus they charge you a $25 "oversize" fee for anything over 1m length.
If you do end up buying a bag, invest in one that has a set of wheels. Your shoulders will thank you.
I rang and asked Jetstar a while ago and asked why they won't take windsurfing gear told me they won't take sailing gear because they put all luggage in those cage thingy's and our sailing gear is too long for those. Nothing to do with the size of the aircraft.