If you need a taxi, remember to look for the official metered white or yellow taxis. There are taxi ranks in many locations throughout the center, but is nearly impossible to hail one driving down the streets, particularly at night. Make sure your taxi is metered; insist on the metered fare, rather than an arranged price.
To call for a taxi within Rome, try 06 3570, 06 4994, 06 6645, 06 551, or 06 8822.