GPU in HEP 2014 will be held at "Sala Gerace" in the Computer Science Department (Dipartimento di Informatica) (map):
Largo Pontecorvo, 3 - Pisa
The conference room is on the 2nd floor of Building C. The first two floors host the INFN (Istituto Nazionale di Fisica Nucleare).
The place is easily accessible on foot from almost anywhere in the city. Bus n.4 from railway station arrives close to the venue (stop "Dipartimento di Matematica").