The best place to start looking for a practice test for the WIA exam is with the Wireless Institute of Australia themselves. Go to wia.org.au/licenses/foundation/trialexam for a trial exam paper.
To obtain an amateur radio license through the WIA, you must first attend a two-day course at your nearest radio club. To find out where your nearest club is, simply head to the WIA website's homepage. Once you take the course, you will be allowed to sit the exam, but you must also take a practical assessment.
If you wanted to take the exam this year, you may need to hurry, as the last exam sittings for 2014 take place in late November. The advanced and regular assessments will cost around $80, the practical test $75, though there a discounts if you are already a member of a nationally recognized radio club.
For more advice and tips, go to mara.org.au/online-resources, or contact the WIA national office on (03) 9729 0400.
YouTube users have a variety of ways of preparing for tests and exams. Here's one from Long Beach City College, USA: