Barcelona has a good public transport network that combines the bus, the “metro” (subway), the tram and the train, which reaches out the metropolitan area. The most convenient way of getting to the different parts of the city is the metro. The frequency of pass is very high, connections between the different lines are usually well indicated and it reaches most of the areas of interest in the city. The cost of tickets has been unified across the different public transport services. Details can be found at Autoritat del Transport Metropolità (ATM).
Bus lines cover almost every part of the city but besides the fact that they also deal with very busy road traffic, it is a bit more complex to get familiar with the different routes and stops. Nevertheless, you may need it to reach specific areas of the city. There is also a tourist bus (covered and uncovered version) that takes you along the main attractive sights of the city (Barcelona Bus Turistic, must purchase specific tickets). Complimentary to the metro and the bus is the recently developed tram, which goes along “La Diagonal”. It may be a good choice to getting around from the conference venue to the nearby Pedralbes park, la Illa and other shopping malls down la Diagonal. Further details, including including timetables and costs can be checked from Transports Metropolitans de Barcelona.
At night, taxis are a competitive choice.
If you know the exact destination address, Barcelona city hall also provides a the Com Anar web service that estimates the best route, including a time estimation, to get from one point to another in the city. Also the public transport service guide you with the transport combination you may require at TMB (Transports Metropolitans de Barcelona) - vull anar.
For additional information on these and other services like car hire, bike rental, etc, visit Alternative transport. A detailed city map displaying services and other practical information can be found at Ajuntament de Barcelona - Plànol de la ciutat.