Take A/22 of Brennero go out to Chiusa - Val Gardena and in 20 minuts you are in Ortisei, after Ortisei there is S.Cristina and then you are in Selva Val Gardena.
Trains from Italy and from Europe stop at the station of Bolzano, Bressanone or Chiusa, and then there are the direct connections with bus for Selva.
The nearest aeroport are Bolzano, Innsbruck, Verona, Monaco e Milano. You can get to Val Gardena with flight low cost! too