If you arrive on a charter flight at Ciampino Airport (tel. 06-65951), you can take a CoTral bus (tel. 800-150008 within Italy), which departs every 30 minutes or so for the Anagnina stop of Metropolitana (subway) Line A. Take Line A to Stazione Termini, where you can make your final connections. Trip time is about 45 minutes and costs 1€ ($1.20). A taxi from this airport to Rome costs the same as the one from the da Vinci Airport , but the trip is shorter (about 40 min.).
Just read this in reverse
taxi from da Vinci airport to the city costs 45€ ($54) and up for the 1-hour trip, depending on traffic. The expense might be worth it if you have a lot of luggage or just don't want to bother taking a train. Call tel. 06-6645, 06-3570, or 06-4994 for information.