Travel
Santiago de Compostela can be reached by plane (SCQ). The airport is connected to the city centre by bus (~1 EUR, timetable here; a convenient stop for the old town is Praza de Galicia) and taxi (21 EUR flat rate to the city centre).
You can also travel to Vigo (VGO) or A Coruña (LCG) airports, less than 100 km from Santiago. From there you can reach Santiago either by taxi or by bus+train.
Porto airport (OPO, in Portugal) has direct connections with several destinations worldwide but it is 200 km from Santiago. From there you can either take a taxi or a bus to Santiago.
Santiago is also connected with Madrid by high speed train (~3.5 hours).
Accommodation
Each participant is expected to find her/his own accommodation. Santiago de Compostela has a large offer of accommodations, from hotels to touristic apartments. The conference venue will be in the old town, around Praza do Obradoiro (main square). Nevertheless, the city is not large and it is almost impossible to get a hotel that is more than 30 minutes walking from the old town.