Tyler suggests that dollarization raises prices. I am in Panama investigating. It´s true that the price of goods here, with the exception of some labor intensive goods like food preparation and taxi service, is similar to the U.S. Despite Tyler´s recondite arguments, however, I think dollarization lowers not raises real prices.
The argument to the contrary is mostly an illusion. When there is an exchange rate the nominal exchange rate can depart far from the real exchange rate. Over a matter of months a country can become very cheap or very expensive for tourists. The real exchange rate, however, is much more stable than the nominal exchange rate. So when dollarization fixes the nominal exchange rate a country is unlikely to become either very cheap or very expensive. Add in the selection argument that tourists visit when the country is cheap and its easy to see why it might appear that dollarization raises prices. (and for residents there is a selection effect also, dollarization happens when the country has been pushed to the wall.)
Overall, however, currency is mostly neutral and in the case of dollarization the effects if anything will be positive. For a country like El Salvador or Panama dollarization brings lower transaction costs and higher quality money which lowers real prices.
Addendum: Tyler, however, is correct about numero 6.