Western Australia is pretty flat, and as such there isn't much climbing in general. That which there is is pretty spread out. Most of the bouldering is on granite boulders and outcrops, although there are some limestone venues too. There is excellent coastal bouldering around the Margaret River area, and good trad in Albany.
Blackwall Reach - A limestone wall thats right on the Swan River, if you come off you get wet!
Generally pretty hot! Much hotter and more humid in the North - much colder and wetter in the South.
There are no specific bouldering guides to Western Australia, although the
CAWA - Check the bouldering sub-forum for information from locals.