The volcanoes are a unique attraction of Chile. They usually present easy glacier ascents and an unique view all around from the top. You will find active volcanoes with lava, roaring fumaroles and thermal springs. Usually they are located in the national parks and therefore well accessible. In some places rangers will check your equipment. Only a few out of the many are listed below. Some are even still virgin. See also Trekking for volcanoes. A good guide book about hiking and mountaineering is the Adventure Handbook Central Chile, to be ordered from the site www.MapsoftheAndes.de 

Interesting links:

www.viajeros.freeservers.com Volcanoes of Argentina
http://earthobservatory.nasa.gov Volcanoes of the Earth (some of S-America are present)