I noticed that Big Day Out tickets will go on sale at 12:01am Friday on the festival’s website (local time for each show I assume) and all other outlets from the start of business on Friday morning. So you’ll be waiting up if you absolutely must have them when they go on sale.
If you’re bored and in Perth on Saturday, Ronan tells me there’s a Tool night being held at the Leederville Hotel at 8pm. Might be worth looking into…