Montepulciano is a walled hill town in Tuscany, built on a sloping and narrow limestone ridge in the heart of the Vino Nobile wine growing area. It's the largest hill town in southern Tuscany and is known for its impressive central square, beautiful Renaissance buildings, churches, and views.
Montepulciano is in southern Tuscany in the Val di Chiana just east of the beautiful Val d'Orcia.
It's about 95 kilometers south of Florence and 150 kilometers north of Rome.
Hourly buses run from Chiusi train station, on the major rail line between Rome and Florence and probably more convenient, to Montepulciano. (Fast trains from Florence to Rome do not stop in Chiusi anyway).
Buses also run to nearby Tuscany towns like Siena and Pienza. Note that buses may not run on Sundays. From the bus station you can walk into the historic center or take the little orange bus. The center is closed to traffic except by permit so if you're arriving by car, park in one of the lots on the edge of town.
The closest airports are in Rome and Florence, see this Italy airports map. There are also some flights into Perugia airport in Umbria.
For those coming from abroad, the best way to go to Montepulciano is to reach Rome or Florence train stations and to take a train to Chiusi (approximately every two hours), then a bus from Chiusi to Montepulciano (approximately every hour)
Link to official italian train site: http://www.trenitalia.com/tcom-en
Link to official bus site: http://www.tiemmespa.it/index.php/Viaggia-con-noi/Orari-e-linee/Siena/Urbano/Siena