[Fork Handles]

Tiger might have a service by then.
Air Malaysia is often the cheapest of the big airlines, but the planes are full of raggies.

I would think booking through a bucket agent well in advance would be best.

Melbourne and Sydney are both exxy for hotels, the best deals are probably just out of the city. In Melbourne try South Yarra (close to the MCG, South Melbourne or St Kilda. Sydney my favourite is Coogee Beach, easy bus to the city and SCG.
Just be sure the game isnt at the Olympic Stadium, well out of town.