Galileo Teacher Training Program (GTTP) is an international program teaching teachers about astronomy. The program is soon to be taken on by the Australian Telescopes Outreach and Education Program. This site also has a large number of downloadable resources.
The Australian Telescopes Outreach and Education Program also offers a range of other Astronomy PDs.
CSIRO Victoria are able to hold Astronomy PDs in your school or at their Centre in Highett
You may even wish to try an online short course with Swinburne Astronomy Online
VSSEC offer a Professional Development day in conjunction with Melbourne Planetarium and CSIRO
TeachMeet Melbourne is a regular meeting of teachers sharing ideas. Free and organised for teachers by teachers, I have found it to be an amazing resource for ideas and networks. If you are not in Melbourne, check for one near you, they are popping up everywhere!