In reply to Doug:
Since a big rockfall the actual cliff at La Foixarda has been covered in wire and climbing in banned. You can still climb on plastic in the old tunnel, but it is frankly rather grim.
The best sport crag within an hour of Barcelona is Gelida, which has a selection of excellent routes between 5 and 8a, with the most quality being in the 6b-7b range. The rockfax guide does a good job of getting you there but the topo is now very out of date. I suggest googling "Gelida topo" or "Gelida ressenyes" for some more up to date (homemade) images. Gelida is extremely popular and on a winter weekend you will likely be queuing for routes below 6a.
Two more okay crags near the city are Pas de la Mala Dona and Penya Ginesta. Both are in the rockfax guide, which covers them pretty accurately as they are both very old (and polished). Both are good in the 5-6c range, though Pas de la Mala Dona has two very nice 7b/+s going up through the cave.
Montserrat has plenty of sport climbing sectors on its south face. The guidebook is "Montserrat Cara Sur", which is now very old (maybe there's a newer one out? I'm not sure). Personally I find Montserrat sport climbing to be repetitive and boring, and I haven't been there for years, but there's a lot of it to go at.
The bouldering near Barcelona is very good with several spots within an hour's drive: Can Bruguera, Sant Joan de Vilatorrada, Savassona, Can Boquet and more. Topos and directions can be tricky to find though, if you're interested then send me a message through my profile and I'll see what I can dig up.
Have fun!