I'm planning to be about a month in Australia and then continue my trip to New Zealand. What is the cheapest method to get a flight from Australia to New Zealand? Does it make a difference from which airport to which airport I fly?
The usual Aussie website for comparing flight prices is Webjet, but in my experience they don't list everything.
Also they charge a booking fee so use it to find a flight but you might get a better price on the same flight elsewhere once you have the details.
I also query on Kayak to double check international rates, and then have a look at the individual websites of Qantas, Air New Zealand and JetStar.
I've also recently built a flight search engine / deals site for Australia - Beat That Flight - where we post deals, and the prices search feature quite often beats deals sites like webjet/kayak, especially on trans-Tasman fares to New Zealand.