Most, if not all local businesses accept dollars as well as pesos. You can exchange pesos to dollars or dollars to pesos at any of the local banks. There are also exchange booths that generally offer more favorable exchange rates.
When converting dollars to pesos - multiply.
When converting pesos to dollars - divide.
As of March 2005, the average exchange rate is 10.90 (aprox.) pesos per $ 1 US dollar.