Hi Eric
There are three good birding apps (and a few free ones that range from very basic to very limited)
Pizzey and Knight Birds of Australia - good info and maps, has calls for nearly all species, though the sound files have been quite heavily processed. App updated 4 weeks ago, so everything current.
Morcombe & Stewart Guide to Birds of Australia - Pretty good coverage, much more natural sound files (recorded by Dave Stewart), but a little out of date re taxonomy, as there hasn't been an update for four years. Also, a few of the maps are famously wrong!
David Stewart Bird Calls of Australia - the most comprehensive collection of bird calls for Australia. Birds are grouped by subspecies and region so it gives a more accurate set of calls for where you are. I tend to use this and Pizzey because I only ever used the Morcombe guide for the calls, but since the publication of the Stewart app I really don't need the Morcombe app for anything.
If you're an eBirder, then definitely use the Explore feature in the app, which shows you the hotspots in the LGA you're in (and you can change the settings to show any area in the world). Great for seeing what's been seen in the last 3, 7, 30 days etc.
The Merlin app, which is so good at identifying birds by call in Europe and North America, is in its infancy here in Australia. All the birds occurring commonly in Europe and NA are included, but to date there are only about 25 local species included. More are added every few months.
There's also a handful of printed guides, some of them a bit big to be called field guides:
Australian Bird Guide (Peter Menkhorst, Danny Rogers et al) published by CSIRO - by far the best book covering all Australian birds, but it won't fit in your back pocket!
The other main ones are:
Field Guide to the Birds of Australia (Simpson & Day)
Field Guide to the Birds of Australia (Pizzey and Knight) paper version of the app, without the calls but lots of extra description
The Slater Field Guide to Australian Birds - a nice slim volume full of helpful illustrations
There is a growing number of photographic "field" guides but none of these are great for ID. It's not possible to show all the plumages of some species in just 3 or 4 selected photos. Some of these volumes do have very good images, though.
I'm surprised the publishing houses are still rolling out new editions of these bird guide books, given how much more useful the apps are.
Morcomb guide