Many towns in Tuscany have tourist information offices, which can be useful resources for trip-planning advice (and sometimes maps). Such offices are typically open from 8:30 to 1 and 3:30 to 6 or 7; those in smaller towns are usually closed Saturday afternoon and Sunday, and often shut down entirely from early November through Easter.
The tourist information office in Greve is an excellent source for general information about the Chianti wine region and its hilltop towns. In Siena, the centrally located tourist office in Piazza del Campo has information about Siena and its province. Both offices book hotel rooms for a nominal fee. Offices in smaller towns can also be a good place to check if you need last-minute accommodations.