They air in various countries the night before so by the next morning or afternoon, the episodes have been streamed (not sure on this part) and made available to watch and download well before it airs in USA (which is just about the last place for SD to air ironically)
I may be wrong but the Australia version is the one that comes out early and I would assume thats because they are ahead in time so their Friday night is way eariler that American/Europe's. So someone from Australia puts it up. Thats what I am lead to believe anyway. Could be totally wrong though.