Here are a few links you may find of interest.

http://www.dia.org.au - Design Institute of Australia

http://www.aila.org.au/information -  Australian Institute of Landscape Architects 

http://www.architecture.org.au - Australian Architecture Association

http://www.architecture.com.au/i-cms?page=1 - The Royal Australian Institute of Architects

http://www.architectswithoutfrontiers.com.au - Architects Without Frontiers

http://www.architects.nsw.gov.au/home.cfm - Registration Board

http://www.apesma.asn.au - The Association of Professional Engineers, Scientists & Managers, Australia (APESMA)

http://www.engineersaustralia.org.au - Engineers Australia

http://www.cibse.org.au/index.html - Chartered Institution of Building Services Engineers

http://www.acea.com.au - Association of Consulting Engineers (ACEA)

http://www.hreoc.gov.au - Human Rights & Equal Opportunity Commission Website

http://www.dimia.gov.au/index.htm - Department of Immigration & Citizenship (including Visas)

http://www.ato.gov.au/default.asp?menu=40 – ATO

http://www.rcsa.com.au - Recruiting Consulting Services Association