Thanks guys for the answers..

PWMTrav I'll be a couple of days on Rome and then I'll spend the weekend and may be a weekday in Florence.
unfortunately I don't have confirmation yet of my hotel, but I assume that it will not be hard to find a TIM store right?

about google maps, is it updated for rome and florence?
I mean can I use it for public transportation and to know the citi??

Also, do you have any other cool app to recommend?
I'm an android user.