http://www.bscc.asn.au/Joomla/
http://www.downsmotorsportclub.com.au/
http://www.hsccq.com/
http://iwmac.org.au/
http://www.mgccq.org.au/
http://www.ndscc.asn.au/
http://www.mx5clubqld.com.au/
These are the ones I deal with in S.E.QLD. There is others slightly further out ie Warrick, Gympie, Maryborough etc. But as a beginner you probably wont be travelling that far.
edit//
If you are gonna do sprints at say Lakeside or QR, then you dont need to do anything with CAMS clubs. You just need to purchase a AASA clubman license from Lakeside or QR. QR has a website.
I was gonna get back into Khanacross this year but a few outside issues force me to hold back. Next year is the year. Iam selling my suspension and wheels to allow purchase for more khanacross friendly parts.