The postcodes that you can send Express Post to and from. Its hard to find on the Australia Post site because they keep moving it:

Location Postcode range(s)
Canberra 0200-0250; 2600-2639; 2900-2920
Sydney and suburbs
Gosford Region
Newcastle
Wollongong Area
1000-1920; 2000-2249; 2555-2574; 2740-2786
2250-2263
2264-2338; 2413-2430
2500-2530
Melbourne and suburbs
Geelong and suburbs
Ballarat
Bendigo
Shepparton/Mooroopna/Kialla
Seymour
Latrobe Valley
3000-3210; 3335-3338; 3340#; 3427-3429; 3750#; 3755#; 3757#; 3765-3767; 3782; 3785-3796; 3800-3810; 3910-3915; 3930-3934; 3975-3977#; 8000-8899
3211-3220
3350; 3353-3356
3550; 3552-3556
3629-3632#
3660-3661
3825; 3840-3844
Brisbane
Gold Coast
Booval/Ipswich Areas
City of Toowoomba
Strathpine/Caboolture
Sunshine Coast Areas
Maryborough City
Hervey Bay City
Bundaberg City
4000-4209
2484-2490; 4210-4299; 9726; 9728; 9729
4300-4305
4350; 4352*
4500-4510; 4520
4550-4601
4650#
4655#
4670#
Adelaide 5000-5199; 5800-5999
Hobart area
Launceston
7000-7019; 7050-7053; 7055; 7172; 7892
7248-7325
To and from Perth
From all above locations to Perth CDB
Only from Perth CBD
(6000-6005; 6800-6899) to:
Canberra CBD
Sydney CBD
Melbourne CBD
Brisbane CBD
Adelaide CBD
Hobart CBD
Launceston
6000-6005; 6800-68992600-2601
1000-1299; 2000-2009
3000-3010; 8000-8010
4000-4004
5000-5005; 5800-5879
7000-7003
7250