I will be on a 2 week tour of Portugal, Spain and France. I have just had my cellular phone unlocked with the suggestion I buy SIM cards as necessary. Will one SIM card work for all of Europe or will I have to buy one in each country. Also we do we buy the cards and how much do they cost. By the way I live in Canada and have had the assurance that my Blackberry will work in Europe. Any help will be greatly appreciated.