How do they celebrate Christmas in Australia?

Obviously there is no White Christmas or Winter Wonderland there because it's in the Southern Hemisphere. It's in the summer there. So I want to know how they celebrate it there. Do they have the same customs we do in America? Do they decorate the trees and have eggnog? What does Santa Claus do when he arrives in Australia. I figure it must be too hot for him to wear that red and white suit. Does he wear a speedo when he crosses the equator?