There is an English version guidebook on Santiago called TODO SANTIAGO (All Santiago) published here in Chile (Editorial Puelche, www.editorialpuelche.cl). The company also publishes some additional bilingual guidebooks and maps, and you can usually find those at the Santiago International Airport and in most of the larger bookstores.
We have the January 2004 TODO SANTIAGO edition. The major in-and-around Santiago sights are listed and the color photography is high quality. If you are just arriving and have a little time to read about the key places to see in Santiago, this book is easy to browse. Just choose what looks and sounds best for your travel, and plan accordingly.