This may be a little bit of an out of date idea - I'm assuming people do still actually go to the cinema nowadays, and don't just wacth the new releases online - on pages like Megavideo, SeriesJonkies, etc. (I recently saw the whole new season of 24 online for free)!
However, there are certain actors that I just can't watch dubbed (think Al Pacino, Robert de Niro, etc.) and I still think this a good resource if you don't want to miss that all important premiere, so here's a list of Original Version Cinemas in Barcelona centre.
Icària Yelmo. Carrer Salvador Espiriu, 61. Metro Cuitadella vila Olympica.
Casablanca. Passeig de Gracia, 115. Metro Diagonal.
Boliche Avenida Diagonal 508. Metro Diagonal.
Renoir Les Corts. Carrer Eugeni d'Ors, 12. Metro Les Corts.
Renoir Floridablanca. Carrer Floridblanca, 135. Metro Urgell.
Verdi. Carrer Verdi, 32. Metro Fontana or Joanic.
Méliès. Carrer Villaroel, 102. Metro Urgell.
Verdi Park. Carrer Torrijos, 49. Metro Fontana or Joanic.
Looking for accommodation for your stay? Try apartments for rent in Barcelona for more freedom and live like a local! Also, for a heads up on the city sights, see this guide to Barcelona.