Jagermeister: It is a Basque name so the correct pronunciation follows the rules of Euskara, not Spanish. The two are completely unrelated. In fact, Euskara is unrelated to any other European language.
JayCee: What's the authority for your assertion? If you are basing it on the Spanish pronunciation the comment above applies. According to Mark Kurlansky it is "a-chay-a." (BTW, if the name rings a bell for anyone, Kurlansky also wrote "Cod," another fascinating investigative history book.)
Incidentally, has anyone ever found a wesbite for Ugartechea?