Both the Hawaiian and Pacific Collections have a great many historic newspapers, dating from the 19th century through present. Many are in microfilm, and most have not been indexed, meaning that if you're searching for a specific event, your only option may be to go to the microfilms and begin reading papers dating from the period you're interested in. However, some have been digitized, and in these cases are searchable and readable online.
News agregators are websites that gather news from a variety of other sources, or in some cases simply offer links directly to other news sources. They generally feature the major news stories of the Pacific and are therefore the best place to start for most basic news research.