OSDC 2007 is in Brisbane this year on 27-29 November (with a tutorial day on
the 26th). $275 early bid registration closes October 14th.
Just follow the instructions at the top of http://osdc.com.au/registration/ to
1. register and 2. pay. (If you are going to pay by credit card/PayPal you
should note the OS7xxxxx invoice number that the registration process
allocates you and re-enter that when you pay.)