Sea routes to Polynesia by Thor Heyerdahl
Origin of the Polynesians by Lorin T Gill
Source: British Museum
A playlist of clickview videos dealing with Polynesian expansion can be found here.
Vaka Moana
Peoples of the Pacific and their origins by 
Sea people by 
The Polynesian expansion across the Pacific: (c. 700-c. 1756) by 
Support materials for "The Wayfinders" PBS focuses on Polynesian seafaring methods on a voyage to the Hawaiian Islands.