Thanks, that will work.if you already have the dollars with you, Joe is right you will need your passport to do it in any bank, the best exchange rate is in Bancomex located in the northeast corner of Sinaloa and Fremont Blvd. in the same shopping center as the coffe bistro and Mexican Inmigration, this bank only gives pesos when using the ATM but their exchange is the highest as of 8-17-2011