Hi Dan,
I think if you check out the Yacht or Sailing clubs you will find one that has a sail training program at very affordable prices. The benefit of this is that it would be structured learning and you would probably gain a certificate such as "Competent Crew" or similar.

Try the Humpybong Yacht Club at Redcliffe. Here is their web site http://www.hyc.net.au/index.htm

Happy sailing. Cheers Cisco

if your local yacht club has twlight series .. races after work on a friday arvo ? we have en down here on lake macquarei .. no compedative no spinakers and great fun... people are allways looking for drew wieght on the side or mabey a second set of hand for cockpit work.. mabey get in touch of the club president and get him to send a email around with ur email adress and details and see if anny one responds

Daniel,
RQYS has its Wednesday Afternoon Gentlemen go Sailing sessions - Skipper registration is about 12pm, and you should give them a call and see if you can get a run! (check out their website - all details are there, and everybody I know who has had a go has had a ball)
South Brisbane Sailing club for dinghy sailing (www.sbsc.org.au) - Saturday afternoons although about to close for Christmas after this weekend, reopens after Australia day. I know you don't want to pay for the school, but it does let you hire a boat to race if you do. There is a good fleet of NS14's, plus Herons (including club boats), but also lasers, again some of which are for hire. If you want to put your name down as possible crew on a private boat at SBSC - drop Leanne the president an email (her address is on the website).
Cheers
Michael Thorpe