Well i noticed you have a topic about australian slang, here is a list of 'true blue' australian slang:
friend: mate
hello: g'day
wow!: struth
i think so: i rekon
yes!: bloodyoath (could be used in this context: man did u just get that flag? answer: bloodyoath i did)
Thats the basic form of australian slang, it has died a little but it is still very prodominent through the every day australian convosation.
The only people who dont use it are foreners and gangsters or emos or other fags.