Copyright law protects the rights of owners and creators, and provides guidelines for how their work can and can't be used.
In Australia, copyright law is set out in the Copyright Act 1968.
Copyright protection is automatic under Australian law and applies regardless of whether the copyright symbol © is present.
The Act gives protection to eight categories:
The owner is usually the author or publisher of the work. The owner may give permission to others to use, publish, edit, play, perform etc.
For more information, read this Australian Copyright Council fact sheet:
An Introduction to Copyright in Australia.