There are ATM machines (Redbanc) all over the city, including the airport.
You can exchange money at the airport, in banks or at Casas de Cambio (Currency exchange offices). Note that Casas de Cambio generally have better rates than banks. Banks are usually open from 9:00 to 14:00. The Casas de Cambio are usually open from 9:30 to 18:00.
For currency conversions, please visit: http://www.xe.com/ucc/
There are cash machines and two banks (Corpbanca and Santander) on San Joaquin Campus. Note that if you want to cash a cheque you will be asked to show your passport. In order to cash a Chilean cheque you need to sign vertically across the front side of the cheque and write your passport number on the reverse side.