Here are some of the websites I regularly visit for news about Melbourne and Australian theatre.
This site is my first stop for all things theatre in Melbourne, both amateur and professional. Here you will find a comprehensive list of all of current and upcoming shows, as well as reviews, interviews, articles and audition notices. I visit this site weekly to keep up with Melbourne theatre. This site often announces rumours of upcoming shows well before they are officially announced.
This site covers a wide range of Australian theatre, including musicals, plays, opera and cabaret, and lets you search by different theatre companies.
This is a site produced by the Independent Theatre Association. It provides a great overview of Australian amateur theatre.
This site is divided up by states of Australia for easy searching. They have also partnered with Lasttix to bring a great range of last minute tickets for shows at discounted prices. I highly recommend getting onto the Lasttix email list as they regularly offer substantially cheaper ticket prices for many Melbourne shows.