Dear all,
First you have to speak english, I spent few months there, no chance to find someone who speaks french :-) Very easy country to meet people as there are many clubs... yacht club (Mort Moresby, Lae, Madang...), golf club... and 99% of the expats stay between expats. Most of them come from Australia and Asia (Philippines...). To meet local people, you have to be introduced and have an interest for their culture and the best it's to take your bagpack and go in the villages to meet them. And all expats (99%) will tell you that you are creazy to do it...
