I am using digicel 3g internet becasue it's cheaper and very easy to start. If you like to use ADSL, you need fixed line telephone line with PNG Telikom. I heard the PNG Telikom service is very bad. I went to PNG Telikom office one day to find out ADSL but only one was sitting at the counter in the office. I just gave up.
Digicel prepaid 80 Kina = 500mb
From my skype experience, you can hear well but they cannot hear me well. But it depends on the weather, time, locatoin etc. I don't think video skype works on 3g internet here.
Other than Skype, it is OK but quite slow, better than nothing.
ADSL is expensive. ADSL speed is range from 128/64 to 512/256 so it is still slower than the rest of the world.
According to Skype you need to have more than 512kbps up for video skype.
Please post if you have another solution.