[quote name='Slynt' post='1723732' date='Mar 18 2009, 14.13']Cool, though a proper translation would be "West Hill" (väster = west, westly, western) (ås = hill)[/quote]
Actually, Västerås comes from Västra Aros, i.e. Western Aros, where Aros is the old name for åmynning - a river's inlet. Östra/Eastern Aros is known these days as Uppsala. The English Westeros is pronounced more or less as Västerås apart from the initial v-sound.
Oh, and V was often spelled with a W in them olden time just as Ä and Å sometimes was mixed with an E or O respectively so I'm sure that there are historic documents bearing the name Westeros.