I flew over with them last year, prior to flying you have to call up and let them know your bringing a bike, because they only allow space for a certain amount of bike boxes each flight.
Its $50 Canadian to get your bike on board. It cost me $150 all up because i filled my box right upto almost 32kgs, seen as though it counts for 1 bag of luggage I figured I might aswell.
It can be a hardcase or cardboard bike box, I took the cardboard version that you can buy from the Qantas desk at most airports. Cost me $16. Make sure to tape the box up a bit with ductape, give it a bit more strength in the handles and the bottom etc so it lasts a little while..