I have driven around Calabria and Sicilia without any problems. Of course, I recommend that you have a basic understanding of Italian or if you know Spanish than you should be fine. Do make sure you plan your route in advance and bring a map or GPS as roads are not marked as they are in the US.
If you are looking for recommendations on where to rent a car, I suggest that you call a local 4 or 5 star hotel in Messina or Taormina and ask for the name of an agency. I paid approximately 50 euros a day for a basic car with unlimited mileage in Tropea.