There is this stuff about blond haired melanesians etc and quite a lot of disussion about migrations from pre-historic caucosauid people to these locations.
here is a new article about a genetic study which indicatges that there is little in common between the polyneisans and melanesians.

The Genetic Structure of pacific Islanders

and the study in detail at PLoS Genetics website

PoLS Genetics - Study : Genetic Structure of Pacific Islanders

Thanks I found this thread very interesting being a Polynesian myself (Maori)

The main issue Id like to point out is this (c&p'd from the 2nd more thorough link) --->

"For simplicity, we refer only to the peoples of Near Oceania as “Melanesians,” although this term ordinarily encompasses additional groups to the east as far as Fiji, who are not covered in this study"

That group not included in the study is quite a substantial group of cultures, who incidentally have strong Melanesian characteristics & looks

Basically, the Polynesian cultures originated from the La Puta people in Taiwan in Ancient times & from there spread out across the Pacific in 2 sweeps, the first taking them to Hawaiki & the 2nd sweep back westward & North peopling Hawaii, Aotearoa, Samoa, Tahiti & Tonga (and so on)