Was there in October.
Ale & Hop[/url:25mq79qz] is a little hipster bar that's totally on top of the Catalan craft scene, and has loads of Italian and US beers, too. Nice nibbles, too, but not the easiest place to find.
This[/url:25mq79qz] is a good bottle shop with most Catalan craft and some rare US beers like Cigar City and Hoppin' Frog. You can do tasters in-store, too.
George & Dragon[/url:25mq79qz] has a misleadingly English pub name but is run by a guy from Pennsylvania; good local beers and lots of Rogue. It's just off Passeig de Gràcia near one of the big Gaudi buildings.
Good luck!