No credit cards for the forseeable future.... they are widely accepted, but the exchange rate will not be good. There are talks about a special virtual bank account for tourists that needs to be funded with wired funds... but still havent seen the fine print and all the details. This system will probably give visitors a better exchange rate, but the system may not be for everybody due to the hassles etc. Best bet it to come down with USD Cash (in very good condition) and get the best exchange rate.
I will post more details as available.....