Whilst it doesn't currently appear to have any feeds from airports in New Zealand, you may be interested in
LiveATC.net, where you can listen to live ATC audio feeds from all over the world.
You may also find their FAQ entitled '
What is required to run a feed?' useful in terms of equipment.
Interestingly, there are no UK feeds (I'm sure there used to be), which
this FAQ explains is due to legal issues...