You can reach Sardegna by boat or by plane. Plane is, by far, the best and fast solution.

The El Faro Hotel, in which the Conference will take place, is located in proximity of the "small black phare" just above the "Porto Conte" text. 
Informations on flights and companies (normal and low cost) can be found at the
Alghero-Fertilia Airport link.
The Alghero-Fertilia Airport is also served by Ryanair and it is at about 10-15 minutes (by car) from the El Faro Hotel.  
El Faro Hotel is at ~ 15-20 minutes from the Alghero city. Alghero is about 10 km from the Airport.

Ryanair @ Alghero - Connections List
Barcelona (Girona) (GRO)
Bremen (BRE)
Dublin (DUB)
Dusseldorf  (Weeze) (NRN)
East Midlands (EMA)
Frankfurt (Hahn) (HHN)
Liverpool (LPL)
London (Stansted) (STN)
Madrid (MAD)
Milan (Orio al Serio) BGY)
Pisa (Florence) (PSA)
Stockholm (Skavsta) (NYO)

Connections between the Airports of Girona (Spain) and Stansted (UK) served by Ryanair:
Connections Barcelona-Girona Airports
Connections London-Stansted Airports  (Heathrow-Stansted ~ 45 min by train)