The nearest railway line is at Zell am See. Here, you'll have to transfer to one of the many buses that travel up the winding valley road. Buses depart from the railway station at Zell am See about every hour throughout the day, stopping first at Saalbach (trip time: 30 min.) and then continuing on to Hinterglemm (40 min.).
If you're driving, take Route 312 southwest from Salzburg to Lofer, and then cut south at the junction with Route 311.
The tourist office (tel. 06541/680068) is in the center of Saalbach but also provides information for Hinterglemm. It's open in winter Monday to Saturday 9am to 6pm, and Sunday 9am to noon; in summer Monday to Friday 8:15am to noon and 1:30 to 6pm, Saturday 8:15am to noon and 3 to 6pm, Sunday 9am to noon.