Australia Post
Useful features include Postcode Search, Postage Calculator, Post Office Locator and International Post Guide.  Services include Mail Forwarding.

Australian Libraries Gateway
The Australian Libraries Gateway (ALG) is a free web-based directory service which aims to have current information about every library in Australia available online - a "one-stop-shop" for information about Australian libraries.

Post billpay
Australia Post offers another way to receive and pay some of your bills online with your credit card.

Whereis Online
The online street directory.

White Pages Online
Look that number up online.

Yellow Pages Online
Find that business online.