XC Race Tracks
This menu is gradually being created. It will contain info on the trails and locations of XC events hosted by PMBC.
Currently available:
You can also try http://www.dpi.wa.gov.au/cycling/1518.asp#mountain . These are more recreational trails but if you are new to mountain biking or Perth, they are a good start as there are often other trails coming off these or nearby.
Another good investment is the maps of the Munda Biddi trail (http://www.mundabiddi.org.au/) for the same reason mentioned above - they have the key fire roads on them which helps in exploring the areas the trails go through.