Information is available at three locations maintained by the Azienda di Promozione Turistica di Roma (APT): a kiosk at Leonardo da Vinci International Airport (tel. 06-65954471), and a kiosk and administrative headquarters at Via Parigi 5 (tel. 06-488991). The headquarters are open Monday to Saturday from 9am to 7pm. The office at the airport is open daily 8:15am to 7pm.
More helpful, and stocking maps and brochures, are the offices maintained by the Comune di Roma at various sites around the city, with red-and-orange or yellow-and-black signs saying COMUNE DI ROMA -- PUNTI DI INFORMAZIONE TURISTICA. The Comune di Roma has a Call Center for tourist information (tel. 06-36004399). They're staffed daily from 9am to 6pm, except the one at Termini (daily 8am-9pm). Here are the addresses and phone numbers: in Stazione Termini (no phone); on Piazza Cinque Lune near Piazza Navona (tel. 06-68809240); at Via Minghetti Marco near the Quirinale (tel. 06-6782988); on Piazza Sonnino in Trastevere (tel. 06-58333457); at Via della Stamperia, near the Trevi Fountain (tel. 06-6796540); at Via Marsala, outside Termini (tel. 06-4740031); at Via del Tempio della Pace, near the Colosseum (tel. 06-69924307), and at Piazza del Campidoglio (tel. 06-6798921).
Enjoy Rome, Via Marghera 88, near the train station (tel. 06-4451843; www.enjoyrome.com), was begun by an English-speaking couple, Fulvia and Pierluigi. They dispense information about almost everything in Rome and are far more pleasant and organized than the Board of Tourism. They'll also help you find a hotel room, with no service charge (in anything from a hostel to a three-star hotel). Summer hours are Monday to Friday 8:30am to 7pm, and Saturday 8:30am to 2pm; winter hours are Monday to Friday 9am to 6pm, and Saturday 9am to 2pm.