Hello
sorry for the lack of answers, this blog is mainly used in French and not English as New Caledonia is an English spoken territory.
If I am not wrong, there is only 1 operator in New Caledonia which provides sim card for mobile phone.
I usually buy the pay as you go phone card but I don't really know if you can call abroad with it.
For the fare to call abroad, I won't be able to tell you as I use Skype (when connexion is good!) to call home.
Hope that helps...